The Byron BY302 portable wireless door chime has a 200 metre operating distance with an 85db rating. It provides a choice of eight melodies and volume control. Self-learning codes will keep the code even when the batteries run out and are replaced. This portable chime can have up to 6 bell pushes controlling the chime. The Portable Chime requires 3 x C batteries (NOT included).The Push requires 1 x 23A battery (included). Operating Distance: 100m.Sound Rating: 90-94dBWeight: 310g.