? 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-4 or M-8 ? All cartridge roll part numbers shown are resin bond, half-glued ? Quarter and full glue are also available for quotation ? 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.