1,Self check when power on, 2,Alarm by 3 step bibi sound 3,LED digital display ... steady running state, can continuously running over 3 years.Fastest alarm speed in industry, 0.15 second typically, true world ... 0.3/0.4-2.0/2.5m.Super power-saving mode, only 1.2Watt in average.Full sensor ... ~15V DCSensing range0.3-3.0mAlarming time0.15s (typical)Power consumptionAve 1.2W, max 1.5WSensing AngleX,Y: 60 ...