This sensor is essentially a reed switch, encased in an ABS plastic shell. Normally the reed is 'open' (no connection between the two wires). The other half is a magnet. When the magnet is less than 13mm (0.5") away, the reed switch closes. They're often used to detect when a door or drawer is open, which is why they have mounting tabs and screws. You can also pick up some double-sided foam tape from a hardware store to mount these, that works well without needing screws. Technical Details * Normally open reed switch * ABS enclosure * Rated current: 100 mA max * Rated voltage: 200 VDC max * Distance: 15mm max Dimensions: * Box size (each side): 29mm x 14mm x 9mm / 1.1" x 0.6" x 0.4" * Cable Length: 305mm ± 12mm / 12" ± 0.5" * Weight (per side): 5.4g https://elecena.pl/product/22722319/magnetic-contact-switch-door-sensor 2023-03-07 https://elecena.pl/product/22722319/magnetic-contact-switch-door-sensor 2023-12-27 https://elecena.pl/product/22722319/magnetic-contact-switch-door-sensor 2024-09-19 https://elecena.pl/product/22722319/magnetic-contact-switch-door-sensor 2024-11-29 https://elecena.pl/product/22722319/magnetic-contact-switch-door-sensor 2024-11-30 https://elecena.pl/product/22722319/magnetic-contact-switch-door-sensor 2025-11-28 https://elecena.pl/product/22722319/magnetic-contact-switch-door-sensor 2025-11-29