Summary I wanted a duct to direct the hotend fan's air over the throat of the hotend. Bolts on in the same spot, and uses the stock fan. It seems to help shorten the thermal transition zone, making the hotend less likely to jam. Print Settings Printer: Geeetech G2s Pro Rafts: Doesn't Matter Supports: No Resolution: 0.2 mm Infill: 25% Notes: Orient it so that the fan side is down on the build plate. Its near the hotend, so I would recommend ABS. 0.8mm walls.