The Plug-In Wireless Door Chime from Arlec is easy to install with no wiring required. It consists of a door push button (transmitter) and (portable chime unit (receiver), with an operating range ofapproximately 50 metres. The chime operates from mains power so no batteries are required for it, however the transmitter uses a 3V lithium battery. Features: wireless therefore easy to install 8 selectable chime tones, including Westminster and Ding Dong operating range of approximately 50 metres, although the actual range depends on location, temperature and battery condition "power on" LED indicator on the chime unit improved circuitry improves battery life randomly selected operating channels to prevent interference with other wireless products plug the chime unit into any standard power point (no batteries required for the chime unit) push button uses 1x3V Lithium battery (the battery for the push button is included) 1 year guarantee Contents: 1 push button (with...... show more