22 Ã— 0.2mmm. Fiber reinforced, highly flexible, high structural strength. Very efficient cutting rate. No discoloration or residues. These aluminum oxide discs are designed for cutting metal alloys and ferrous metals such as aluminum, nickel, cobalt, copper, titanium, brass, bronze, solder and steel. Designed to cut both on the periphery and on both faces. Ideal for use in the dental, aerospace, automotive, electronics (solder), engineering industries and for luthiers/musical instrument makers, gun and knife makers and general metalworkers. These fibercut cutting wheels are very flexible and very robust due to being re-enforced with fiber. They have a very efficient cutting rate and will create no discoloration or leave any residues. Do not exceed 25,000 rpm.