The MC-38 Door Magnetic Sensor Normal Open is a reliable and widely used security sensor designed to detect the opening and closing of doors or windows. It operates on a Normally Open (NO) configuration, meaning that the circuit is open (disconnected) when the door or window is closed and closes (completes the circuit) when it is opened, triggering an alert or action in security systems. This magnetic sensor consists of two parts: a magnet and a switch. The switch is typically mounted on the door frame, while the magnet is attached to the door or window. It's commonly used in home security systems, alarms, and automation projects, offering easy installation and dependable performance.