A24R - General Purpose. Aluminum oxide grain. For general purpose, low cost cutting only. Combines fast cutting and long life. Ferrous metals (iron, steel, welds, etc.). Specifications: Max RPM - 8500, 5/8-11 Super-Lock hub. Tech Info: For use on angle grinders. Aggressive cutting performance over a wide range of applications. Super-Lock Hub on all 5/8-11 threaded arbors is the safest, vibration-free design. All sizes reinforced with the highest quality fiberglass for maximum safety and performance.