Helps hold the smart extruder+ together when it's taken apart, and to get the tolerances right. For what it's worth, I also made it so the pins are accessible on the back.

Has holes in the back for 4 max 5mm diameter magnets if you want magnetic attachment.

Possible upgrades to the design I might make in the future:

• Taller nozzle holder
• Holes to access the case screws from the back
• Extension at bottom to show where end of nozzle should be
• Markings to show where heat-spreader fans, heat block, etc. should line up