Recommended drill bit size should be:
20 - 21mm in size.
Step 2 - Drill for Magnet piece.
Drill a corresponding hole in your door. The hole should be 15mm deep. As stated, the position of this hole should
align exactly with the hole you just created in the doorframe. Again, use a 19mm wide drill bit.
Unlike the main unit, 19mm drill bit should be used.
With your door and door frame prepared and the drill holes created, it's now time to mount both parts of your
Recessed Door Sensor.
Step 3
Insert Main Sensor into the hole you created in the door frame then secure it using two screws.
Step 4
Place a small amount of white glue (PVA) inside the hole you created for Magnetic Sensor. Then, place the sensor
over and into the hole. Next, insert it by tapping gently on it with a rubber hammer.