DGBRSM MC-33C Normally Closed Flush Mounted Window Door Contact Sensor White Plastic Magnetic Reed Switch

["High-quality materials: Made from premium plastic, it is durable and safe, so you can use it with confidence.","Easy to install: The screw terminals are compact, making wiring more convenient. The closed-loop magnetic contact uses a terminal block connection to accommodate wires.","NC stands for normally closed: When the magnets are brought together, the circuit conducts electricity (the light turns on), when the magnets are separated, the circuit no longer conducts electricity (the light turns off).","Applications: As a door contact sensor for burglar alarms, this product is ideal for metal doors and windows.","Package contents: 1 piece MC-33C alarm reed switch."]