Based on the stock E3D V6 fan duct (https://www.thingiverse.com/thing:340312) but converted to fit a 40x40mm Noctua fan.
I converted my Ender 3 over to the YouMakeTech extruder setup but didn't have the original E3D V6 cooling fan so I made an adapter to fit both a 40x40mm Noctua fan but also added a spot for a M3 insert to allow it to act as the bottom cooling fan mount as well.
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The author remixed this model.
Extended the duct and increased the fan side to allow for the mounting of a 40x40mm fan as well as integrate into the youmaketech extruder setup.