Summary This is a snap on adapter for kleingeist's 40MM duct cooler that will alllow you to mount to a Makerfront i3 pro Mk8 extruder. Simply snap it around the extruder stepper and use a 6MM screw to secure the fan duct. This is the ring duct i utilized. http://www.thingiverse.com/thing:2004786 First project in Fusion 360 . Print Settings Printer: Makerfront i3 PRO Rafts: No Supports: Yes Infill: 20% How I Designed This Fusion 360