Magnetic Reed Switch Normally Open Door Sensor MC-31

From the shop's description

The reed switch is simply a magnetic activated switch, as long as a magnet is close to it the reed switch will remain closed. This switch should close when the included magnet is within 15mm of the switch. Once the magnet is removed, the switch opens, breaking the circuit. Specifications: MC-31 Normally Open (Switch is closed when the switch and magnet are together) Color White Rated current: 100(mA) Working voltage: up to 40 V Operating distance: more than 15mm, less than 25mm Mounting holes: distance between them is approx. 52 mm Size: 64x13x13mm (1) Size: 64x20x13mm (2) Connection The sensor can be easily connected to any chip with a microcontroller, e.g. an Arduino. By attaching a pulling up resistor or by running an internal pull-up, the read can be implemented in digital form. Includes: Sensor The magnetic element Mounting screws