Features: . White surface mount magnetic contact reed switch kit with pigtail for home metal door or window security alarm system. Normally closed type; when the switch and magnet are close to each other, the switch is closed, otherwise it will be open. The reed switch is an electrical switch operated by an applied magnetic field. Designed for use with alarm systems. Suitable for use in residential and commercial windows, doors, etc. Equipped with double-sided tape for easy installation. Note: No external power supply required; connect directly to wired or wireless alarm control panel GND and N.C. ports. This item is not suitable for iron doors, as it may reduce the sensor's magnetic performance. Specifications: Item Type: Door Sensor Magnetic Switch Material: ABS Model: MC-31 Color: White Size: 6.22cm / 2.44in (Approx.) Actuation Distance: 16mm Rated current: 100mA Rated voltage: 100V DC Operating distance: more than 15mm, less than 25mm Rated power: 3W Connecting mode: NC (normally closed) Quantity: 1 Set (other accessories shown in the picture are not included) Notes: 1. Conversion: 1cm = 10mm = 0.39 inch 2. Please allow 0-1cm error due to manual measurement. Please ensure you are comfortable with this before purchasing. 3. Due to differences in monitor displays, the image may not reflect the actual color of the item. Package includes: 5 Pairs x MC-31 Wired Door Window Sensor (no retail packaging) 20 x Screw