SaitZ-Tech - Specialty. Tough zirconium grain. High performance cutting and notching for the toughest applications. Ferrous metals (iron, steel, welds). Stainless steel, high tensile alloys. Specifications: Max RPM - 8500, 5/8-11 Super-Lock hub. Tech Info: Unique, thin Type 27 shape can be used on all angle grinders in accordance with ANSI B7.1. Special bond formulation offers the fastest cutting, longest lasting thin wheels. Externally reinforced with fiberglass layers to provide ultimate safety in a thin wheel. Super-Lock Hub on all 5/8-11 threaded wheels is the safest, vibration-free design.