Greenbrook Wired Doorchime with battery or transformer powered, has been specifically designed to complement all types of decor, whilst being simple and easy to install. The chime receivers on models DH020A-C and DH021A-C is connected to the bell push/transmitter via bell wire. It is not connected to the mains power and therefore requires 3 x C cell LR14 batteries or transformer to operate. · · · Clear sound · · Classic wired chime · · Traditional ding dong sound · · 1 year warranty