UHPPOTE Normal Closed Wired Screw-Terminal Surface-Mount Magnetic Contact for Window Door Security (Pack of 5)
Switch Type: NC (Normal closed type)
This Contact Works with Any Access Control or Burglar Alarm System Available
This contact can't connect directly to power, it works with your alarm system provide a switch signal. Working current under 12V
Great for use in family and factory window, door. etc.
NC means Normally Closed: When the magnet together, the circuit is conductive (light on); When the magnet separate, the circuit is not conductive (light off).