Here is a small efficient TAZ3 filament cooling fan. The orientation is quite difficult to print, requires a lot of support, however I managed to print it in the orientation that the STL is exported in. The final design incorporated features for easy mounting, using the same bolts all round. Compact space usage, lightweight. You'll need a 1 x 50mm x 50mm fan (40mm mounting hole spacing). 6 x 3M 20mm bolts, washers and nuts 2 core cable for the fan along with connectors (or solder it) EDIT: I had incorrectly specified a 40mm fan, however the fan measures 50mm the holes are 40mm apartHow to install this thing Follow the same instructions as on the Lulzbot website for the fan they sell, that'll tell you how to wire it up. After you've run your wires, simply screw the fan to the duct and then screw the duct to the head on the right hand side. You should have two brass inserts that the fan duct aligns with. How I designed this thing In the last image you can see several iterations of this thing. First, I put the nozzle in the wrong direction! The second one didn't really work as it cooled the heater and was too close to the action that vibration could make it hit. The third one worked well but limted the X-Axis movement and to be safe required manually trimming the lower portion of plastic with a knife. The earlier versions needed different length bolts in different places, had some restrictions on how the thing was mounted making it quite difficult and tedious to install.