Power supply mode: battery power supply Power supply voltage: 110-240 (V Power consumption: 1 (W) Scope of application: home, villa and office Product specifications: black, white Special note: 1. AC doorbell, receiver (indoor unit) use household power supply, just plug it directly into the socket, no battery, convenient for environmental protection! The transmitter (outdoor unit) uses one battery for about one year 2. Super receiving is suitable for home, office building, hotel, building, dormitory, factory, construction site, etc. 3. Using the same doorbell in a range will not interfere with each other! Using wireless high-frequency transmission technology, same frequency and different codes, effectively avoiding the troubles caused by mutual interference and false noise between neighbors Warm reminder: The linear remote control distance of this product is strictly tested not less than 300 meters in the open and obstacle-free. It can meet the needs of different home environments, and it is no problem for ordinary homes to separate anti-theft doors and a few walls. Feature 1: Anti-interference and no crosstalk. Feature 2: Receiver smart flashing light Feature 3: Long-distance wireless signal reception. Feature 4: Adjustable volume and music installation is simple and convenient (default Dingdong Dingdong) 3 levels of adjustable volume 38 music optional