When building fume extraction for my 3D Printer Cabinet, I got a 6-inch inline fan and split it between a couple of cabinets. I quickly designed this splitter to be compact to easily fit in the space I have available.

I have since added this adapter to my paint booth to have two 4-inch ducts connected to the booth, feeding into a 6-inch inline fan to extract the fumes.

Print using three walls at a 0.28mm layer height.