• Premium aluminum oxide abrasive for long life • Heavy, durable X-wt. cotton backing makes these points durable and flexible • 36-60 grit is recommended for removing heavy burrs, stock removal, removing flash and parting lines and removing rust, scale and pit marks • Excellent abrasive product for breaking edges • Recommended mandrel is M-21 • Cartridge are strips of abrasive cloth rolled and glued to form a solid shape that is designed to break down during use and reveal the next layer of abrasive. There are mounted on a mandrel and used on high speed grinders on inside surfaces and inside corners where other forms of abrasives cannot reach.