Feature: 1. NO NC Switch: The magnetic switch has a normally closed function. When the two parts are combined, the switch is turned on, and when they are separated, the switch is turned off. Normally open function is the opposite. 2. Application: Magnetic contact sensor switch can be added to existing wired alarm system, suitable for wooden doors or windows, ideal for protecting doors. 3. High Sensitivity: The use of high magnetic magnets and reed switches makes the magnetic contact switch more sensitive and efficient. 4. Safe Material: The magnetic reed switch adopts ABS engineering fire retardant and flame retardant material, which is safer and more convenient to use. 5. Easy Installation: The door magnetic switch adopts surface mount and screw installation method, and the installation is convenient, dependable to use. Specification: Item Type: Magnetic Reed Switch Material: ABS, Magnet Scope of Application: Door Frame, Wall, Door Connection Method: Screw Connection Output Type: Normally Open, Normally Closed (NO/NC) Induction Distance: Approx. 20-30mm / 0.79-1.18in Installation Method: Surface Mounted, Screw Installation Current Voltage Power: 0.5A 10V 10W Size (One Side): Approx. 55x13x11mm / 2.17x0.51x0.43in. Package List: 4 x Magnetic Reed Switch8 x Screw