Aluminum oxide is durable and the most common abrasive grain Type 27 depressed center wheels are used for cutting off and portable grinding Reinforced design helps provide safety, strength, and straight cuts Resin bonds soften under the heat of grinding, releasing dulled abrasive grains The reinforcement reduces breakage and helps provide straight cuts Norton Gemini RightCut Right Angle -Off Wheels Quality aluminum oxide for consistent performance at an economical price. Durable bond balances cutting speed, wheel longevity, and steady performance. . . Pack of 25