Features: White wired magnetic contact reed switch kit for home door or window security alarm system Normally closed type, when the switch and magnet is close to each other the switch is disconnected, otherwise it will be connected Each part is equipped with double-sided foam adhesive, effortless to install Working Principle: The magnetic reed switch is consist of switch and the magnet, and the switch parts is made of reed switch and the pigtail. The magnet is coved by the plastic or alloy shell. When the switch and the magnet is apart form or close to each other in the certain range, the switch will turn on or off automatically, thus it will inform the installed items's place changing. Specifications: Model: MC-38 Color: White Voltage: DC 100-110V Rated Power: 10W Contact Capacity: 0.5Amp Current Switching Maximum Distance Distance: 12-24mm One size fits all: Approx. 2.7x1.3x0.8cm/1.06x0.51x0.31" Quantity: 5 Sets Note: This is an alarm, whether alarm or not depends on the switch is on or off, means that it is normally closed and no alarm under normal circumstances. Please allow 0-1mm error due to manual measurement. pls make sure you do not mind before you bid Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! No Retail Package Package Contents: 5 Sets x MC-38 Wired Door Window Sensor