Super Abrasive CBN replacement wheels for sharpening steel chains, for both the professional chain sharpener and the weekend sharpener; these saw chain sharpening wheels are for you. They are preshaped and hold their shape, have an aluminum core to run cooler, create virtually no dust, and are known to sharpen 1000"s of chains. They are new and unused 4" diameter (D) with a 7/8" arbor hole (H) that dimensionally match the pink wheels usually provided with the sharpener, and will fit the Oregon Mini and other equivalent machines. They are 1/8" thick (T) for 1/4 and .325 pitch chains. These wheels are not recommended for carbide chains which would use diamond.