You will need one of the top.stl, one arm.stl and 6 body.stls. The body is intended to be glued together and should have a nice fit on the mounting arm. In the arm, you can insert an M3 nut and screw to hang the Netatmo sensor. I printed the top and body parts upside down with support (the body parts with brim) and 100% infill because of the small studs for mounting them together. The arm was printed with 60% infill to make it sturdy enough. The body parts were glued together with UV-curing adhesive (superglue or similar will also work) and the body was put on after the whole thing was mounted to the wall with two 4mm screws.