??? ????50mm????????thingiveres????????????????????? ???????? ????GRABER i3?????????????????????????????? ?????M3?????????????????????????????????? English: I have some 50mm case fans, but I didn't find 50mm fan mount that can cool the hotend and the print at the same time. so I make one. It works great at my GRABER i3. I tested it for about 4 hours, and nothing wrong happened. You need two M3 nuts and four nylon strips to assemble the fan to the mount and the mount to the extruder.