Ceramic aluminum oxide is a self-sharpening grit that is harder, tougher, and lasts longer than aluminum oxide, and is for use with heat-sensitive materials like aluminum, stainless steel, and titanium Type 29 angled style is more aggressive than type 27 style and is used for weld blending, deburring, deflashing, edge chamfering, stock removal, and grinding and finishing in one step Phenolic backing prevents disc from scratching the workpiece and offers durability and reinforcement of the disc Designed for use at a 15- to 35-degree angle to dissipate heat Unthreaded round hole for attachment to grinding tools