These are housings for Z-Axis limit switches using TLE4905L magnetic hall-sensors, plus mounts for the magnets. Since we didn't have much space to mount mechanical endswitches on our CNC-Mill, I decided to use hall sensors. The sensors come as three legged PG-SSO-3-2 ( Plastic Single Small Outline Packages ) and one needs a way to connect a cable and mount them somehow. The magnets are 8x1mm neodyme magnets, so this works only for machines cutting non magnetic materials. I installed the sensors, soldered the cables and used 2-component glue to fix and encapsulate the sensor (to hold everything in place while applying the glue, I used capton tape) I printed this with PLA, since the part gets bended quite a bit when mounted, watch out for your part placment.