12 volt. This compact grinder provides optimum portability, delivers professional sharpening results almost anywhere without the need to remove the chain from the saw. Sharpens 1/4”, 3/8” LP, .325”, 3/8” and .404” pitch chain. Operates on a 12-volt battery and has heavy duty battery terminals. Comes complete with one (1) grinding wheel, wheel dressing block and wheel contour template.