This is a cooling fan mount for the MakerGear Mosaic printer. The printer comes with two fans: a small one for cooling the extruder and a large one for cooling parts being printed. The Mosaic instructions explain how to mount the extruder fan, but no provision is provided for mounting the cooling fan.I was able to use extra hardware that MakerGear supplier with the printer for mounting the cooling fan. The extruder wire harness includes extra connectors for expansion. I used one pair to power the cooling fan. I wired the cooling fan to D9 on the RAMPS board. This allows your skeiner to turn the fan on and off. See http://reprap.org/wiki/File:Arduinomega1-4connectors.png. D9 is located in the upper left.