Sensor to determine the position of the window handle.
It fits very well on the "HOPPE" window handle with oval cover (66mm).
Based on the case of joschi2009:
It is a complete rebuild in Fusion360.
The battery cover snaps onto the case and the side panels are lowered to allow the battery to slide in and out. The channels for the cables are provided with rounded edges. So you can print without a support. The reed contacts fit exactly in the openings. The magnet for the square socket ring can be pressed in with a pair of pliers. You need no glue.