While printing on my Printrbot Simple I found that on longer prints my extruder would start skipping. It wasn't filament jamming, it was the motor itself skipping. So on advice of the community I decided to test a fan pointed at my extruder motor to keep it cool. After the cooling fan was installed, my motor no longer skipped. I used the existing y-arm bolts to secure the mount. This is the fan I purchased and it works perfectly. http://www.amazon.com/gp/product/B000RD0RDU/ref=oh_details_o00_s00_i01?ie=UTF8&psc=1 I removed the pins from the wire connector on the fan and inserted them into the fan connector about 6 inches down the wire harness.