Power supply: DC 9-15V adapter (not included) or 3 pieces of AAA battery (battery not included)
Induction method: active infrared sensor
3 modes: voice alarm, music, human voice in "VOICE" mode:, Doraemon, Ninhao Huan Ying Guang Ling; "Music" mode in "alarm" mode: keeps you aware of intruders; in: like a doorbell, with 32 music to your guests