This custom designed fan duct was specifically created for Antminer bitcoin miners, but will work with any 120 mm fan. As miners, we know how important it is to cool mining equipment and keep temperatures low. Just replace the fan guard with our fan duct using your existing screws and see results immediately. The duct was designed to fit standard 4 in vent hose and to keep air moving. These shrouds are 3D printed using ABS plastic, which is a durable thermoplastic and able to handle to high temperature produced by mining equipment. Does not include 4 in vent hose or clamp. Will not work with Antminer S7 single fan design. Depending on color availability, item may be black or blue. *Antminer is a registered trademark of Bitmain Technologies. We are not affiliated with Bitmain Technologies.