Roughneck Bar-Mount Chain Saw Sharpener File your chain with professional accuracy while it&#39;s still on the bar Sharpener attaches in moments and can be operated from a 12V vehicle battery, so sharpening in the field is convenient 4 1/4in. wheel dia. is 3/16in. thick Sharpens 0.13 thickness for 0.325in. chains, and 0.19 thickness for 0.404in. chains Rebound plate ensures uniform pressure on chain at all times