30pcs RC-33 NC Recessed Wired Security Window Door Contact Sensor Alarm Magnetic Reed Switch White Plastic Ball Bearings 54 inch / 16

54 inch / 16

alloy and many ther abrasive materials

Elegant embedded hidden design and brushed finish

dinner and coffee table and so on

30pcs RC-33 NC Recessed Wired Security Window Door Contact Sensor Alarm Magnetic Reed Switch White Plastic Ball Bearings 54 inch / 16Description: 1. 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 ). When make order,pls check carefully! 2. These are the door contact sensors that are in use with any and all commercial or residential card access systems as well as all security burglar alarm system. 3. Work as an anti theft alarm, perfect for metal door and window.