Wide Application - Compatible with all door openers. Can be widely used in access control systems, parking lots, defensive walls, doors and windows, balconies, garages, passages and other places. Ideal for installation in security systems in schools, office buildings, hospitals, courtyards and more. Stable signal transmission - high power infrared transmitter and receiver. The transmitter produces a reliable, invisible infrared beam up to 65 inches (20 meters). When the infrared beam is interrupted, the relay will switch the signal output. WATERPROOF & UV PROTECTION - Fully waterproof and dustproof egg-shaped housing, sunlight filtering housing, can work in harsh environments. Easy installation. Reliable Use - Equipped with advanced safety technology, it provides multiple protection and security. If an obstacle is encountered, the photocell's infrared beam will automatically stop or reverse the door to protect your safety and property. EASY INSTALLATION - Install each pair in opposite positions. Then there is an infrared field between these two sensitive parts. When someone crosses the infrared zone, the detector will send an alarm signal to the security alarm host (not listed here). Specification: black Material: PC (waterproof, UV protection) Detection range: outdoor: 20m; indoor: 30m Working voltage DC12V~24V Power supply current 50mA Detection distance 20 meters Trigger time 50ms Item size: 76 x 49.2 x 21.6mm / 3.0 x 1.9 x 0. 9 inch Packing List: 1 x Pair of IR Sensors (Transmitter and Receiver)