Check the listing for details. Fosmon WaveLink Add On Wireless Magnetic Doorbell Door Sensor [Transmitter Only]. Color: White, Condition: New. Listed at 9.99 USD. Fosmon WaveLink Add On Wireless Magnetic Doorbell Door Sensor [Transmitter Only] Expand Fosmon WaveLink Doorbell Systems Perfect solution for expanding your Fosmon Doorbell System with this additional door sensor transmitter. Compatible with: 51004HOM - Fosmon WaveLink Wireless Entry Alert Doorbell 51005HOM - Fosmon WaveLink Wireless Motion Doorbell Alert Sensor 51007HOM - Fosmon WaveLink Wireless Door Open Chime 51009HOM - Fosmon WaveLink Wireless Entry Alert Doorbell (Black) Magnetic Door Sensor With your Fosmon WaveLink doorbell system installed, this magnetic door sensor activates when the magnetic stripe is separated. This transmits a signal to the plug-in portable receiver (not included) and alerts you with a ringtone every time the door is opened. Modern and Contemporary Design Never miss anyone at the door. The wireless and portable design works well in home, work, retail stores, salons, and business environments. Built-in LED Indicator The transmitter features an LED indicator that creates a visual alert for the hearing impaired. Easy to Install Wire free and easy to install. Versatility Each receiver can be paired with up to 10 transmitters, and each transmitter can be paired with up to 10 receivers. Specifications: Maximum 500 feet or 150 meters operating range in open area LED indicator Transmitter Battery: 12V 23A Alkaline Battery Transmitter power consumption: