SpzcdZa 3Sets Magnetic Reed Switch Normally Open Closed NC NO Door Alarm Window SecurityMagnetic Door SwitchMagnetic Contact SwitchReed Switch for GPSAlarm or Other DeviceDC 5V 12V 24V Light

???SpzcdZa Magnetic Reed Switch Normally Open Closed NC NO Door Alarm Window Security ??? Please contact us via amazon order when you have any questions or problem, we will make you 100% satisfy. ??NO (normally open),switch is closed when magnet come to the switch. Switch will open when magnet leave. ??NC (normally closed),switch is open when magnet come to the switch. Switch will close when magnet leave ?Switch Type: NO/NC, circuit is connected when magnet is near the switch. ?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. ?Screw Mounted for easily install.