This is a small device called a reed switch on the module.
When the device is exposed to a magnetic field, the two ferrous materials inside the switch pull together and the switch closes.
When the magnetic field is removed, the reeds separate and the switch opens. This makes for a great non-contact switch.
You can mount reed switch on the door for alarming purpose or as switches.
This sensor needs to be used together with EASY plug control board.
Features
Connector: Easy plug
Working voltage: DC 3.3V-5V
Working current: ≥20mA
Working temperature: －10℃ to＋50℃
Detection distance: ≤10mm
Dimensions: 39mm*20mm*18mm
Weight: 4.6g