Slim profile mini wireless doorbell,does not interfere with other socket positions when inserted into the socket. 1 Call Button + 3 Wireless Musical Doorbell Receivers for Home Elderly Shop Call, Black 1 set includes: 1 call button+3 indoor music ringtone receivers+1 adhesive block+1 12V23A battery+1 prompt sticker+1 screwdriver+1 instruction manual.
eBay