Power consumption in sleep mode approximately 10 μA. Up to 2 years of operation on one CR2450 battery (estimated).
When triggered transmits the battery level charge and contact status (OPEN/CLOSE).
Can be used with normally closed and normally open contacts.
Automatic restart in case of a hang-up.

Note

A gateway is required. For details see "RF Gateway".

Full config example for Home Assistant

mqtt:
  sensor:
    - name: "NAME"
      device_class: "voltage"
      unit_of_measurement: "V"
      state_topic: "homeassistant/rf_sensor/ID/open_close"
      value_template: "{{ value_json.battery }}"
      force_update: true
      qos: 2
  binary_sensor:
    - name: "NAME"
      device_class: "door"
      state_topic: "homeassistant/rf_sensor/ID/open_close"
      value_template: "{{ value_json.state }}"
      payload_on: "OPEN"
      payload_off: "CLOSE"
      force_update: true
      qos: 2