2x Magnetic Reed Switch Normally Open Closed NC NO Door Alarm Window Security

The reed switch is an electrical switch operated by an applied magnetic field. Designed for use with alarm systems. Great for use in family and factory window, door. etc. Net Weight: 80g; Material: ABS; Transmitting Distance: 3-15mm Package Content: 4 Sets x Magnetic Door Swith; Size: 55 x 12 x 11mm / 2.2 x 0.47 x 0.43(L*W*H)