Allows you to cool passive PCIe GPUs in workstation cases. Noise test video: http://youtu.be/V4w5BXtjZpY Designed and tested on HP Z800 series workstations, but should fit all full size ATX cases with recessed PCI bays. Extracts up to 2x double wide passive GPUs (installed adjacent to each other). See instructions for suggested fans. Things you will need besides printed parts: Be sure to read full instructions.Decide if you will use 92mm or 80mm fan (see section below for fan choice suggestions) Print one of everything, except 2x thumb screw feet. The bracket frame should be printed with 3 perimeter layers, and at least 50% infill density (cross-hatch). All other parts must be printed fully dense. Use ABS or HIPS. 2x M3 bolt with hex head (eg. the one shown in picture is this Amazon item: http://amzn.com/B001378FAQ) Superglue an M3 bolt into each thumb screw foot 6mm thick x 10mm wide Neoprene strips with adhesive backing. Example: http://www.clarkrubber.com.au/strip-neoprene.html Stick these to the flanged end (wider) of the bracket. Ensure there are no gaps. Push the bracket against the back of the PC case and adjust the thumb screws out so they push out against the sides of the recessed bay. With about 20% compression, the Neoprene will become airtight. If M3 hex head bolts are hard to come by, you can make an equivalent yourself. Cut the phillips head off a regular M3 screw and superglue an M3 nut at the end to act as the hex head. Make sure fan direction is extracting (pulling air from inside case to outside) Tested with this 80mm fan http://goo.gl/IZiGcw and this 92 mm fan http://goo.gl/EzRbzx Note that the 80mm fan running full speed at 40 dB is likely too loud to have beside you. If using a 92mm fan (greater static pressure), consider using a fan controller to control speed in order to reduce noise to an acceptable level (while still providing adequate cooling). You should consider the above fan specs as a guide only. Approx 50+ cu.ft/min can adequately cool two 235W GPUs running at full power. If running only one GPU, simply install the PCI slot covers on the unused slots.