MMU2 Frame Holder for Bear Full Upgrade - easily (re)moved

All props to pekcitron for this design; I just took the f3d files he provided and added a hook so that the MMU can clip onto the frame without screw hardware (like the original mount does on the stock frame). I left the screw holes so you can still screw it down if you want to, it just has a bit more mechanical stability.

Following in the footsteps of the original maker I've uploaded the f3d and step files as well.