FeaturesQuick install transformers, built to last so you should have fewer call backsFits in standard junction box run one wire and the door chime is ready for use installation convenience saves time allowing you to move on-the next project quickerFor safety, ensuring you have a quality, reliable transformer that will pass inspectionJunction box transformer design makes for an easy and quick connection to low voltage wiring, insert into the single-gang junction box and the transformer is safely concealed behind the wallOne 16 V, 10 VA transformer needed for a single chime