Wireless Doorbell, 2 Transmitters and 2 Plug-in Receivers No Battery Required for Receiver 58 Ringtones | Coolqiya2021 New800ft to 1000ft Long Range Transmission strong working signal remote control doorbell for various material door or wall, including glass, metal, wood Multiple Door Bells Chimes & Buttons System Easy to expand add on 20+ remote buttons (transmitters) or receivers. 58 Ringtones and 5 levels Volume to Adjust The doorbell ring will keep the settings when power is removed, no need to reset. Easy Installation 1. Simply plug receiver into socket; 2.