The Byron DBY-22311 Wireless Doorbell comes with a portable chime unit, giving you the flexibility to move your door chime throughout your home, garden or garage. The portable unit requires 3 x AA batteries (not included) and will ring up to 150 metres (open distance) from the bell push.  Easy to install, with no wiring required. Choice of 16 melodies, adjustable volume & compatible with all other Byron 'DBY' products. Features: Wire free, weatherproof, 16 melodies, volume control, operating distance 150m, fixings included. Batteries required: 3 x AA (not included) and 1 x CR2032 battery (included).