This is a mountable extruder fan enclosure. I'd hardwired my extruder fan to 12V on my power supply, once I'd purchased a dedicated part cooling fan. However, I was annoyed it was already running, even when the extruder wasn't. So, I put a classic toggle switch inline with the positive wire going to the fan, and created this mount so I can have the switch easily accessible from the front of the printer.

RepRapGuru Prusa i3 Clone

No

No

.15mm

10%

You can get away with not using any supports if you put the switch-hole side, face down on the print bed. In this configuration, nothing overhangs by more than 45 degrees