Alarm Magnetic Reed Switch Roller shutter sensor Roller Shutter Door Detector Sensor Roller shutter sensor, heavy duty overhead door contact sensor Armored cable in 380mm or 480mm length Wider Gap for reduced false alarms Closed Loop, open loop and SPDT types 1. Housing: zinc 2.Gap:50-70 mm 3.Current: 0.5A, Voltage:12V 4.Surface mounted with screws, leads 530mm standard length, with armored cover cable of 380mm or 480mm