Dont run to the hardware store every time you need the chain harpened on your chain saw. Save time and money by sharpening it yourself with the Pro-Series Electric Chain Saw Sharpener. It is easy to use when mounted to a bench, wall or vise, and it adjusts to all chain designs. The 4-1/4 inch x 1/8 inch grinding wheel spins at 4200 RPM to get the teeth good and sharp.