Specifications: Main material: Alloy plating shell /stainless steel pipe thread /Reed switch Power Requirements: 1*23A 12V battery (Included) Working current: less than 10mA Quiescent Current: less than 3uA Transmit Freqency: 433MHz Wireless transmission distance: more than 50M Transmitter size: 7x3.5x1.5cm Features: Suitable for roller shutter doors, garage doors. Metal zinc alloy housing For home burglar alarm system, important kits of home security. With adjustable bracket , easy for mounting. Surface mounted on the ground with more than 50 mm operation gap. Widely used, Suitable for rolling shutter doors installed in garages and shops. Installation: Stick part metallic magnet on the edge of the roller shutter/rolling door, and stick part metallic sensor on the fixed frame of roller shutter/rolling door Note: The distance of these two parts shall be less than 3-5 cm when the roller shutter/rolling door is closed. Usage: Pull out the antenna of the transmitter. When the roller shutter/rolling door is opened from the closed position, LED will turn on red light for 5 seconds; the sensor will be triggered and will send alarming signal to the main unit. Package Content: 1X Wireless Rolling Door Sensor(included 1* 12V 23A battery) Note: This rolling door sensor can not work alone. It works with most alarm system in the market. Check if your alarm system support 433mhz