MIG135 Knurled Drive Roller (Key Way Style)
Product Review (submitted on March 4, 2013):
Once you get this on the drive shaft, it works great. Seems to feed even when I get the wire feed too slow and it sticks to the collet. Getting it to fit on the driveshaft is a lot harder than the one that comes with the welder. The keyway seems to be REALLY tight. I had to fuss with the index key to get it to go on.