This is a Case for Raspberry Pi boards. Designed to work with a 28mm marine USB and/or HDMI extender, and a 12mm momentary 12vdc switch with LED, neither are required for use. Uses 10mm magnets, and standard M3 hardware. Glue nuts in the nut traps, magnets in the magnet traps, and let dry for 1 day before use (or whatever you glue says). Make sure your magnets are facing the correct direction! One side has an alignment peg that is first inserted, then swiveled into place, where its held in with screws. this side mounts the Pi also. The opposing side mounts with magnets allowing for ease of accessing the Pi. Cables can run through the caps between the middle and sides, or out one of the two rear 28mm holes. The base gets screwed into the middle, this is easier to do before the side is screwed in. The extender rings are there to give you a spacer if you need more room internally. just stretch the spacer to the height you need in your slicer. I think the space on the switch looks nicer than without, also. I updated the model to hold the pi at an angle after i had issues with cable strain. my pictures show the previous design and I only used 1 screw to hold it in, at the angle i changed the model to include. A fan is recommended, although there are inlets and outlets for convection flow. The rhino (.3dm) file includes 2 decals on the Rpi board which significantly lower the viewport response, just FYI. use the BAKE command to eliminate the decals if viewport performance is an issue. The AMAZING Pi4 model came from a fellow designer here: go like their stuff! - https://grabcad.com/library/raspberry-pi-4-model-b-1 I used this FANTASTIC PS5 model as a basis for checking my case proportions etc, go like their stuff too! - https://grabcad.com/library/playstation-5-3