NC Wired Surface Mounted Alarm Magnetic Door Contact Sensor Door Window Reed Switch Sensor with Double Side Tape for Security 4 Sets

["Product Name: Magnetic Door Switch.","Designed for use with alarm systems. Widely used in security window door cabinet contact.","Material Quality: crafted from plastic, the surface mounted magnetic door switch is a reliable asset choice for your home security, which ensures longer service life with its sturdiness and resistance.","Operation Principle: NC means normally closed; If the magnet is closed to this switch, the signal is conductive, otherwise, if the magnet is far away from this switch, the signal is disconnected; This working principle is ideal for alarms, LED, door openers, and more.","Package Content: 4 x Magnetic Reed Switches window door sensors along with 16 screws."]