The Wireless Doorbell Super Easy To Install- Plug the doorbell receiver into a socket and fix the doorbell transmitter on anywhere you want with the included accessories. The doorbell wireless range from the transmitter to the indoor receiver is up to 1000 feet(300m),it adopts advanced wireless transmission technology(FSK+FHSS) to avoid the wireless signal interference from other wireless devices and can go through the doors/walls/floors/and et The doorbell receiver has 35 optional melodies and 5 adjustable volume levels(includes Mute mode). Expandable up to 32 transmitters Reliable&Durable- Focus on the electronics and wireless transmission field to ensure HTZSAFE has enough experiences to make the wireless doorbell system reliable and durable Wireless Doorbell, Doorbell