• Premium aluminum oxide abrasive for long life • Heavy, durable X-wt. cotton backing makes these points durable and flexible • 150-320 grit is recommended for fine blending, cleaning, finishing and polishing • Excellent abrasive product for breaking edges • Recommended mandrel is M-4 or M-8 • 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.