Features: Wide Application - Works for all door openers. Can be widely used for access control system, parking lot, defense wall, door and window, balcony, garage, passage and other places. Great to install for security system in school, office building, hospital, house yard, etc. Stable signal transmission - high power infrared transmitter and receiver. The transmitter creates a reliable, invisible infrared beam up to 65in (20m). When interrupt the infrared beam, the relay will output switching signal. Waterproof and UV proof - fully sealed waterproof and dustproof egg-shaped cover, sunlight filtering case, it allows you to work in a hostile environment. Easy Installation. Reliable in Use - Featuring advanced security technology that provides multiple protection and security. Photocell infrared beam will make the door stop or reverse automatically if an obstruction happens to protect your safety and property. Easy to Install - Install each pair at opposite positions. Then there is an infrared area between these two detecting parts. When someone passes the infrared region, the detector will send an alarm signal to the security alarm host(not listed here). Specification: The black color Material: PC (water proof, UV proof) Detect Surface: Outside: 20m; Interior: 30m Speed detection: 30ms Infare-Red Frequency: 1.92Khz Wavelength: 940nm Voltage: DC 12-24 Input Curren: RX 15mA - TX 30mA Relay output: A1 36W Item Size: 76 * 49.2 * 21.6mm / 3.0 * 1.9 * 0.9in