Imperial Doorbells are mechanically operated, requiring no batteries, wiring or electricity. The doorbell simply fits onto the inside of your front door and gives maintenance free, reliable service. The doorbell uses a clockwork action, and needs only an occasional winding of the dome. They are made in England. They give a loud ring, using the door itself as a sounding board, and will continue to ring as long as the bell push button is pressed. Visitors can clearly hear that your doorbell is in working order. They offer an alternative to wireless doorbells where UPVC door frames (with metal backing for strength and security) can cause problems with wireless signal strength. The clockwork mechanism is released by a thin rod that passes through the door to a bell push button on the outside.