Top 10 Best Teacher Doorbell For Classroom

WIRELESS DOORBELL KIT Includes everything you need for DIY installation 1 outdoor remote doorbell transmitters and 1 plug-in smart doorbell receiver, double sided tape, anchors, screws. An A23 battery is included and will last for up to 3 years.. EASY TO SETUP Our portable doorbell easily pairs and connects so you can make your wireless doorbell battery powered. Customize it by simply selecting frommore than 50 doorbell chime sounds. Has 4 volume settings, perfect for naptime or parties.. LONG RANGE Our patented technology uses the highest quality microchips and does not need wifi or bluetooth. The signal from the wireless bell ranges up to 1000 feet. Great for large homes, apartments, offices, and warehouses. U.S. Pat. No. D800005. SMART TECH Not only have we made the traditional door bell ringer wireless, but we made it smart too. It will remember your customized settings and has sleek, modern LED lights that illuminate and blink for guests to easily spot at night. Truly reliable and weather proof, will operate between temperatures of -4F to 140F.. VERSATILITY Our wireless doorbells work great for any occasion - apartment homes, townhomes, small businesses, warehouses, offices and condo properties can benefit. Whether you're using it outdoors for your front gates, back fences, or mailboxes or indoors for teachers seeking helpful classroom organization and management, there is always a good use for SadoTech.

Quick And Simple The installation requires no tools or electrical expertise The setup for this battery operated door bell is easy and convenient while contributing a stylish accent to the face of any home. Sound Library Do not commit to one single sound every time the door rings This wireless doorbell chime is not bound to any one sound Containing a library of 17 music tones and 35 chimes You have the choice to pick one you like or change it any time you wish. Not Only Doorbell The chime has a strong and unique sound An ideal instrument to be used by the hearing impaired It can be utilized as a classroom doorbell for teachers or as a call button to communicate throughout the house. A New Age For Doorbells Looking for a security system Maybe some motion detectors or a window alarm Know that the set can be customized with add ons such as pet doorbells and additional receivers. Housewarming Gift For Home Did a friend just rent a new apartment or is a coworker buying a house These wireless doorbells for home would make a terrific addition to their.

PAIRS CONNECTS EASILY FOR quick, frustration-free installation anywhere in your home. WHILE OTHER doorbells wireless are DIFFICULT TO SET UP or DONT WORK CONSISTENTLY, door bells by SadoTech extend OVER 1000FT of RANGE in open areas are PROVEN TO WORK THROUGH DOORS WALLS. Great for large homes, apartments, offices warehouses. And with BATTERY LIFE of UP TO 3 YEARS, youll never miss a chime Use as door chime for business when entering or classroom doorbell for teachers. THIS WIRELESS DOORBELL KIT IS the perfect starter for any wireless door bell user. KIT CONTAINS 1 wireless doorbell transmitters and 1 plug in smart doorbell receiver, double sided mounting tape, anchors, screws and A23 BATTERY INCLUDED. Sleek, modern LED INDICATOR lights illuminate both transmitter receiver can be set at 4 VOLUME SETTINGS, from low for naptime to high during a party. Our extensive COLOR SELECTION means youll find the right door bell push button to suit your style.. BUILD THE ULTIMATE SMART door bell system With multiple wireless door bells you can CONFIGURE each door with A DIFFERENT CHIME or ringtone. KNOW EXACTLY WHICH DOOR your visitors are calling from. For homes or offices with multiple entry points, this is CONVENIENT TIME-SAVING. Youll soon wonder how you lived without it. And UNLIKE SOME OTHER doorbell wireless, this door bell by SadoTech is truly WATERPROOF WEATHERPROOF to -4F140F for a system that lasts for years to come.. OUR PATENT-PENDING SOUND CHIP holds the LARGEST SELECTION of classy, high-quality ding-dong chimes, NO TINNY, ANNOYING ringtones. With 52 TOTAL RINGTONES at 4 VOLUME LEVELS, youll feel good knowing our ring chime MEMORY CHIP STORES your chosen doorbell chime selections even when unplugged or turned off. LISTEN FOR YOURSELF Just SCROLL DOWN to the Technical Specs section below click the Specification Sheet link to DOWNLOAD the PDF. Open the PDF and play all 52 ringtones.. AT SADOTECH, OUR GOAL IS to provide INNOVATIVE, HIGH-QUALITY PRODUCTS at a price everyone can afford. QUALITY IS KEY We love that our products bring ADDED SECURITY, CONTROL peace of mind to you, our customers. NEED SPARE BATTERIES, extra add-on buttons, receivers, sensors or a CUSTOMIZED DOORBELL button Visit our store www.amazon.comsadotech. If, for any reason, you dont love your wireless doorbells by SadoTech, reach out and WE WILL MAKE IT RIGHT..

WIRELESS DOORBELL KIT Includes everything you need for DIY installation 1 outdoor remote doorbell transmitters and 1 plug-in smart doorbell receiver, double sided tape, anchors, screws. An A23 battery is included and will last for up to 3 years.. EASY TO SETUP Our portable doorbell easily pairs and connects so you can make your wireless doorbell battery powered. Customize it by simply selecting frommore than 50 doorbell chime sounds. Has 4 volume settings, perfect for naptime or parties.. LONG RANGE Our patented technology uses the highest quality microchips and does not need wifi or bluetooth. The signal from the wireless bell ranges up to 1000 feet. Great for large homes, apartments, offices, and warehouses. U.S. Pat. No. D800005. SMART TECH Not only have we made the traditional door bell ringer wireless, but we made it smart too. It will remember your customized settings and has sleek, modern LED lights that illuminate and blink for guests to easily spot at night. Truly reliable and weather proof, will operate between temperatures of -4F to 140F.. VERSATILITY Our wireless doorbells work great for any occasion - apartment homes, townhomes, small businesses, warehouses, offices and condo properties can benefit. Whether you're using it outdoors for your front gates, back fences, or mailboxes or indoors for teachers seeking helpful classroom organization and management, there is always a good use for SadoTech.

WIRELESS DOORBELL KIT INCLUDES - 1 transmitter button simultaneously triggers 2 chime units. Note The 2 chime units can each be configured to ring with DIFFERENT melodiesringtones.. SMART DOORBELL RING CHIME SYSTEM - Multiple door bell receivers can be configured to RING WITH DIFFERENT door chimes or ringtones to let you know which transmitter was triggered. It's smart and very convenient feature, especially for multiple doorway entries.. LONG RANGE WIRELESS DOOR BELL - Our Sadotech wireless doorbell system has a long range operation with the receiver at over 1000 feet. It features a built in receiver memory too that retains door bell chime or ringtone selection even when the receiver is unplugged or powered off.. COMPLETE SET - This doorbell wireless kit offer a complete set of or a base start kit that includes 1 plug in doorbell receiver, 1 battery operated receiver and 1 remote doorbell transmitter button, double sided stickers, anchors, screws, A23 battery is included. Perfect as door chime for business when entering and even as classroom doorbell for teachers.. LISTEN TO OUR ELECTRONIC DOORBELL CHIMESRINGTONES BEFORE YOU BUY - Just SCROLL DOWN to the Technical Specs section below and click on the Specification Guide link to DOWNLOAD the PDF file.

PAIRS CONNECTS EASILY FOR quick, frustration-free installation anywhere in your home. WHILE OTHER doorbells wireless are DIFFICULT TO SET UP or DONT WORK CONSISTENTLY, door bells by SadoTech extend OVER 1000FT of RANGE in open areas are PROVEN TO WORK THROUGH DOORS WALLS. Great for large homes, apartments, offices warehouses. And with BATTERY LIFE of UP TO 3 YEARS, youll never miss a chime Use as door chime for business when entering or classroom doorbell for teachers. THIS WIRELESS DOORBELL KIT IS the perfect starter for any wireless door bell user. KIT CONTAINS 2 wireless doorbell transmitters and 2 plug in smart doorbell receiver, double sided mounting tape, anchors, screws and A23 BATTERY INCLUDED. Sleek, modern LED INDICATOR lights illuminate both transmitter receiver can be set at 4 VOLUME SETTINGS, from low for naptime to high during a party. Our extensive COLOR SELECTION means youll find the right door bell push button to suit your style.. BUILD THE ULTIMATE SMART door bell system With multiple wireless door bells you can CONFIGURE each door with A DIFFERENT CHIME or ringtone. KNOW EXACTLY WHICH DOOR your visitors are calling from. For homes or offices with multiple entry points, this is CONVENIENT TIME-SAVING. Youll soon wonder how you lived without it. And UNLIKE SOME OTHER doorbell wireless, this door bell by SadoTech is truly WATERPROOF WEATHERPROOF to -4F140F for a system that lasts for years to come.. OUR PATENT-PENDING SOUND CHIP holds the LARGEST SELECTION of classy, high-quality ding-dong chimes, NO TINNY, ANNOYING ringtones. With 52 TOTAL RINGTONES at 4 VOLUME LEVELS, youll feel good knowing our ring chime MEMORY CHIP STORES your chosen doorbell chime selections even when unplugged or turned off. LISTEN FOR YOURSELF Just SCROLL DOWN to the Technical Specs section below click the Specification Sheet link to DOWNLOAD the PDF. Open the PDF and play all 52 ringtones.. THE SADOTECH WIRELESS DOORBELL is not only functional but also ADA compliant, making it an excellent choice for the hearing impaired. It's also perfect for classroom use, as a business door buzzer, or for home use. With its long range, waterproof design, and easy installation, it's the ideal solution for all your doorbell needs. Plus, with its sleek, modern design and extensive color selection, it's sure to complement any decor..

PAIRS CONNECTS EASILY FOR quick, frustration-free installation anywhere in your home. WHILE OTHER doorbells wireless are DIFFICULT TO SET UP or DONT WORK CONSISTENTLY, door bells by SadoTech extend OVER 1000FT of RANGE in open areas are PROVEN TO WORK THROUGH DOORS WALLS. Great for large homes, apartments, offices warehouses. And with BATTERY LIFE of UP TO 3 YEARS, youll never miss a chime Use as door chime for business when entering or classroom doorbell for teachers. THIS WIRELESS DOORBELL KIT IS the perfect starter for any wireless door bell user. KIT CONTAINS 1 wireless doorbell transmitters and 2 plug in smart doorbell receiver, double sided mounting tape, anchors, screws and A23 BATTERY INCLUDED. Sleek, modern LED INDICATOR lights illuminate both transmitter receiver can be set at 4 VOLUME SETTINGS, from low for naptime to high during a party. Our extensive COLOR SELECTION means youll find the right door bell push button to suit your style.. BUILD THE ULTIMATE SMART door bell system With multiple wireless door bells you can CONFIGURE each door with A DIFFERENT CHIME or ringtone. KNOW EXACTLY WHICH DOOR your visitors are calling from. For homes or offices with multiple entry points, this is CONVENIENT TIME-SAVING. Youll soon wonder how you lived without it. And UNLIKE SOME OTHER doorbell wireless, this door bell by SadoTech is truly WATERPROOF WEATHERPROOF to -4F140F for a system that lasts for years to come.. OUR PATENT-PENDING SOUND CHIP holds the LARGEST SELECTION of classy, high-quality ding-dong chimes, NO TINNY, ANNOYING ringtones. With 52 TOTAL RINGTONES at 4 VOLUME LEVELS, youll feel good knowing our ring chime MEMORY CHIP STORES your chosen doorbell chime selections even when unplugged or turned off. LISTEN FOR YOURSELF Just SCROLL DOWN to the Technical Specs section below click the Specification Sheet link to DOWNLOAD the PDF. Open the PDF and play all 52 ringtones.. AT SADOTECH, OUR GOAL IS to provide INNOVATIVE, HIGH-QUALITY PRODUCTS at a price everyone can afford. QUALITY IS KEY We love that our products bring ADDED SECURITY, CONTROL peace of mind to you, our customers. NEED SPARE BATTERIES, extra add-on buttons, receivers, sensors or a CUSTOMIZED DOORBELL button Visit our store www.amazon.comsadotech. If, for any reason, you dont love your wireless doorbells by SadoTech, reach out and WE WILL MAKE IT RIGHT..

WIRELESS DOORBELL KIT INCLUDES - 1 transmitter button simultaneously triggers 2 chime units. Note The 2 chime units can each be configured to ring with DIFFERENT melodiesringtones.. SMART DOORBELL RING CHIME SYSTEM - Multiple door bell receivers can be configured to RING WITH DIFFERENT door chimes or ringtones to let you know which transmitter was triggered. It's smart and very convenient feature, especially for multiple doorway entries.. LONG RANGE WIRELESS DOOR BELL - Our Sadotech wireless doorbell system has a long range operation with the receiver at over 1000 feet. It features a built in receiver memory too that retains door bell chime or ringtone selection even when the receiver is unplugged or powered off.. COMPLETE SET - This doorbell wireless kit offer a complete set of or a base start kit that includes 1 plug in doorbell receiver, 1 battery operated receiver and 1 remote doorbell transmitter button, double sided stickers, anchors, screws, A23 battery is included. Perfect as door chime for business when entering and even as classroom doorbell for teachers.. LISTEN TO OUR ELECTRONIC DOORBELL CHIMESRINGTONES BEFORE YOU BUY - Just SCROLL DOWN to the Technical Specs section below and click on the Specification Guide link to DOWNLOAD the PDF file..

ASSIGN A DIFFERENT RINGTONE TO EACH BUTTON. RECOMMENDED FOR TEACHERS Looking for classroom learning resources These are must-have school supplies for teachers for classroom that will help avoid yelling during class. It comes with with variety of colorful, vibrant push buttons. These teacher supplies for classroom are great for classroom organization.. CONDUCT FUN CLASS QUIZ CONTESTS This easy to install wireless doorbell for classroom device is used for fun educational games to organize class activities from kindergarten games to math games for first grade.. LISTEN TO THE RING CHIMES BEFORE YOU BUY - Just SCROLL DOWN below to the Specification Guide link and click to DOWNLOAD the PDF file. Open the PDF and play all 52 ringtones..

WIRELESS DOORBELL KIT Includes everything you need for DIY installation 1 outdoor remote doorbell transmitters and 1 plug-in smart doorbell receiver, double sided tape, anchors, screws. An A23 battery is included and will last for up to 3 years.. EASY TO SETUP Our portable doorbell easily pairs and connects so you can make your wireless doorbell battery powered. Customize it by simply selecting frommore than 50 doorbell chime sounds. Has 4 volume settings, perfect for naptime or parties.. LONG RANGE Our patented technology uses the highest quality microchips and does not need wifi or bluetooth. The signal from the wireless bell ranges up to 1000 feet. Great for large homes, apartments, offices, and warehouses. U.S. Pat. No. D800005. SMART TECH Not only have we made the traditional door bell ringer wireless, but we made it smart too. It will remember your customized settings and has sleek, modern LED lights that illuminate and blink for guests to easily spot at night. Truly reliable and weather proof, will operate between temperatures of -4F to 140F.. VERSATILITY Our wireless doorbells work great for any occasion - apartment homes, townhomes, small businesses, warehouses, offices and condo properties can benefit. Whether you're using it outdoors for your front gates, back fences, or mailboxes or indoors for teachers seeking helpful classroom organization and management, there is always a good use for SadoTech.

WIRELESS DOORBELL KIT Includes everything you need for DIY installation 1 outdoor remote doorbell transmitters and 1 plug-in smart doorbell receiver, double sided tape, anchors, screws. An A23 battery is included and will last for up to 3 years.. EASY TO SETUP Our portable doorbell easily pairs and connects so you can make your wireless doorbell battery powered. Customize it by simply selecting frommore than 50 doorbell chime sounds. Has 4 volume settings, perfect for naptime or parties.. LONG RANGE Our patented technology uses the highest quality microchips and does not need wifi or bluetooth. The signal from the wireless bell ranges up to 1000 feet. Great for large homes, apartments, offices, and warehouses. U.S. Pat. No. D800005. SMART TECH Not only have we made the traditional door bell ringer wireless, but we made it smart too. It will remember your customized settings and has sleek, modern LED lights that illuminate and blink for guests to easily spot at night. Truly reliable and weather proof, will operate between temperatures of -4F to 140F.. VERSATILITY Our wireless doorbells work great for any occasion - apartment homes, townhomes, small businesses, warehouses, offices and condo properties can benefit. Whether you're using it outdoors for your front gates, back fences, or mailboxes or indoors for teachers seeking helpful classroom organization and management, there is always a good use for SadoTech.

Designed with the elderly in mind, our life alert systems for seniors give you and your loved ones peace of mind knowing that help is only a button-press away.. Compact and convenient, our call button comes with a lanyard and can be worn around the neck for easy access.. Our SadoTech wireless doorbell is easy to set up and use, and can even be detached if needed. Just plug in the receiver to any outlet and wear the lanyard around your neck. Built for durability, our waterproof caregiver call button has a silicone-covered transmitter button for maximum protection against spillage.. More than just a caregiver pager, our versatile bell also doubles as a wireless doorbell for classrooms and office buildings. Use it to signal students without the yelling.

Long Range - Operating range up to 1,000ft300m in open area when there are no obstructions, ensures you to hear the bell and answer the door in time.. Waterproof Dustproof - Waterproof rating ensures the rain day usage perfectly. Sleek flat panel makes cleaning dust a piece of cake. Just rest assured to put it outside for convenience.. 36 Different Ringtones Adjustable Volume - The doorbell features 36 chimes and 4 level adjustable levels 25db to 85db to suit your needs. Flashing light with audio alert indicators which is easy for people including the hearing impaired to notice.. Easy to Install Use - Easily plug receiver into an electrical outlet no batteries required for main receiver. The push button can be fixed to the doorframe with the attached adhesive tapes. Simply mount the doorbell where needed and you are ready to go.. Multi Use - It is fit for home, apartment, office, villas and more. You can use our doorbells to train dogs, using it to quiet down classrooms, seniors and disabled use doorbells as assisted living call pagers Ensures that you will not miss any visitors, you can hear the sound even from back garden..

Easy to InstallJust plug the mini receiver into a socket and fix the transmitter on a wall with the accessories provided Includes 2 screws, 2 anchors, a battery, a double-sided tape, and even a screwdriver. Will not interfere with other equipment in your home or those of your neighbors, ensures you will never miss a visitor. This wireless doorbell set is by far the most convenient choice for your home and business.. Waterproof Robust Push ButtonA stylish modern design in classic white, excellent materials keeps itself from getting higher temperature interference. Waterproof Dustproof, remote transmitter button is rated IP44 weatherproof. Works between -22 F to 158 F withstand various harsh weather conditions, acceptable for outdoor use. Our door bells are certified with CE, RoHS, FCC.. Ultra Long Operating RangeOperating range up to 1000ft 300m in the open area, ensures you to hear and answer the doorbell in time. Either you are occupied a few rooms away or on another floor, in the garden or kitchen, you will always be easily informed when someone is calling from outside, never worry about missing visitors.. Widely Applied 38 RingtonesA perfect wireless doorbell kit for home, apartment, school, villas, office, warehouses, hotel, factory, hospital and more. There are 38 different ring tones with 4 levels of adjustable volume from 25db to 85db. The stereo speaker delivers rich and crisp sound, easily choose and set your favorite tones as you wish Flashing light indicators which are easy for people including the hearing impaired to notice.. WarrantyOur BO YING wireless doorbell enjoys the 5-year warranty and friendly customer service. We stand behind all of our high quality products and each is backed by the strongest Manufacturer Support. If you have any issues with our Wireless Doorbell, we're here to make things right..

Modern and Practical DesignOur wireless doorbell comes with stylish appearance and practical functions. Lightweight and sensitive, there are illuminated halo and LED strobe alerts on the receiver. Operating range up to 1000ft in open area, offer you fast indication, which ensures you to hear the bell and answer the door in time.. 5 Volume 52 Ringtones For Your Choice There are 52 ringtones and 5 adjustable volume levelsincluded silent mode to choose from. The 52 kinds of ringtones can be chosen as per you like. With adjustable volume from 20db to 80 db, it will suitable for most of your room.. Easy Installation No batteries plug receiver required. The easily installed transmitter will be set up in only several minutes.And there are 2 ways to place your receiver-by sticker screws.. More Than a Door Bell Expand applications by yourself, e.g. use it as a dog or a cat training assistant device.. Reminder WARRANTYIf continuous button pressing is required, please press again the button after the ring sound stopping rather than continuous button.You will get a full refund or a brand new replacement if you are not satisfied with it..

Easy to Install This SECRUI wireless doorbell has been paired before it reaches you. It can be set up in under a minute by simply plugging the receiver into the socket, eliminating the need for wiring or electrician installation.. Long Distance This wireless remote-control doorbell with high-frequency electronic technology uses the FM signaling protocol, which provides robust anti-interference feature and one-to-one signal pairing. There's no need to be concerned that the signal will not reach the door next to you. And in an obstacle-less environment, the detecting distance can reach up to 1000 feet.. Wide Range of Chimes The doorbell has been updated with 58 songs, including Merry Christmas ringtone, and 5 adjustable-volume levels. You can choose from options like two buttons and one receiver, one button and two receivers, two buttons and three receiver set, etc. as needed.. Weather Resistant and Energy-Saving The doorbell is composed of premium ABS, which offers high performance in terms of fire and flame resistance. The bell can operate in temperature range of -4 F to 140 F and provide IP55 waterproof and dust-proof protection. The receiver adopts an optimized circuit design while the transmitter does not use power until pressed. The battery life is for about 3 years.. High Quality with Exquisite Appearance The doorbell ringer exhibits stylish design and subtle, innovative industrial aesthetics. We have high-precision placement, industry-leading automation equipment and regulate the quality of the product. If there are any issues, please get in touch with us right away so we can fix them..

Portable Design Versatile Use The wireless doorbell does not necessitate WiFi or power sockets. The receiver and transmitter can be positioned at your convenience and utilized as a pager. The receiver may be situated on a tabletop or kept in your bag as you prefer. Whether you're in the cellar, the garage, or the garden, you'll always be aware of your visitors.. 36-Month Long Battery LifeThis wireless doorbell comes equipped with a sleep function. After a few minutes of non-activity, the door chime kit enters sleep mode. Press any button to awaken the receiver. The receiver operates on 3 AA batteries not provided and can last for up to 36 months of daily usage, reducing the need for frequent battery replacements. RGB Light Indicator Cordless DoorbellThe RGB light indicator on the battery-powered receiver flashes upon transmitter activation and receipt of a signal. The high-decibel 110 dB volume can alert those who are hearing impaired or elderly. You can silence the front door bell when no ringtone is needed and rely on the RGB light to visually notify you when someone is at the door.. 60 Melodies, 5 Volume Levels Memory FunctionThis outdoor waterproof wireless doorbell offers 60 selectable melodies, 5 adjustable volume levels ranging from 0dB to 110dB, and a silent mode to cater to your preferences. The memory function ensures that the cordless doorbell kit recalls the last chosen melody and volume setting, even in the event of a power outage.. 1300feet Cordless RangeThe TECKNET wireless doorbell boasts a working range of up to 1300feet in open spaces without disrupting other nearby cordless devices. A robust and stable radio signal ensures you'll never miss a visitor. Note The provided transmitter contains batteries, whereas the receiver does not Requires 3 AA batteries.. IP66 Waterproof DustproofThe wireless doorbell flaunts a stylish contemporary design, with superb materials that shield the doorbell push button from elevated temperatures and interference. The battery-operated front doorbell is waterproof up to IP66 and robust enough to withstand extreme environments. It maintains a wireless transmitter in wet weather conditions and operates in diverse climates from -4F to 140F.. Life Time SupportShould you experience any issues whilst using the product, don't hesitate to reach out to our professional customer support team, and take advantage of TECKNET's 36-Month Warranty Registration Required..

Multiple Melodies Choice The Wireless outdoors doorbell offer 58 pop chimes and 5 levels Volume0-110 dB, different chimes set for different doors so you can know which door you have a visitor come in. LED flahse indicators are suitable for the elderly and hearing impaired, You can be add as required, choose more button or receivers. Working Ultra-long Range The signal from the Door bell ringer wireless which can fully cover 1,000 ft. It works through thick walls, trees and metal siding buildings, ensures you to hear and answer the door bell in time. Either you are occupied a few rooms away or on another floor, never worry about missing visitors. Wireless Doorbells perfect for HomeClassroomOffice. Reliable Waterproof ButtonExcellent materials make the doorbell showing high performance in fire and flame resistance,snowstorm, or Scorching Sun harsh weather conditions. Wireless Doorbell is rated IP55 dustproof and waterproof , working temperature ranges from -4 F-140 F. Easy To UseThe wireless door bells kit uses wireless transmisssion tech, No wiring is required And the installation is simple. The doorbell consists of two parts, The transmitter and the receiver. When the transmitter is pressed, the receiver plyas the preset ringtone after receiving the signal from the transmitter, Frustration-free installation anywhere in your home.Great for large homes, apartments, warehouses. Use as door chime for business when entering or classroom doorbell for teachers. EXPANDABLEFlexible design according to your actual needs. You can choose the quantity of transmitter and receiver as you like, which can be freely matched with each other. No matter in the bedroom or on the balcony, you will never miss any visits from outside of your door.