Battery operated - easy to install - totally portable - no wires or cables Long range radio wave transmission - up to 70 metres - so can be placed anywhere in large homes, gardens and garages The door chime receiver has a slotted hang hole and can also be fee standing. The door chime receiver can be hooked onto a screw using its slotted hang hole. It can be easily removed, placed on a bookshelf, table or carried with you - making it totally portable. Good neighbors feature easy adjustment of channel selection will stop interference from neighbors who have the same door chime Choice of two chime tones - Ding Dong and Westminster.