Power supply : dc 9-15v adaptor(not included) or 3 pieces of aaa battery(battery not included)
induction method : infrared sensor triggered3 modes:
voice alarm music, at "voice" mode: human voice,;
at "alarm"mode: keeps you aware of intruders;at
"music" mode: just as a doorbell,with 32 music to welcome your guests
detection angle: horizontal angle of 110 degrees, vertical angle of 15 degrees
volume: 4 levels adjustable (can't adjust volume at alarm mode)
available in many pieces