Unique emery rubber compound embedded industrial diamond particles, extra-fine, fine, medium grit * Highly-effective at removing rust, corrosion, paint from metal and other hard material * 18 bits in a variety of sizes, 6, 12, 20mm * Less harsh than mounted stone or diamond-on-steel bits; leaves smooth, polished surface * 1/8" shanks fits Dremel & other rotary tools - an amazingly versatile accessory set