Zirconia alumina abrasive is self-sharpening, more durable than aluminum oxide, and for use on steel and stainless steel * Type 29 angled style is more aggressive than type 27 style and is used for weld dressing and edge finishing * Phenolic resin backing offers durability and reinforcement * Free of iron, sulphur, and chlorinated fillers, making it safe for use on stainless steel * Unthreaded round hole for attachment to grinding tools