Saitech Ultimate Performance - Stainless Steel. Combines fast cutting with extremely long life for tough cutting applications. Stainless steel, high tensile alloys. Ferrous metals (iron, steel, welds, etc.). Specifications: Max RPM - 6600, 5/8-11 Super-Lock hub. Tech Info: Manufactured with patented 3M Cubitron grain to outlast standard aluminum oxide wheels. Unique bonding system lets you make faster burr-free cuts. Designed to provide very long life for fewer wheel changes and less downtime. All sizes internally reinforced with the highest quality fiberglass for maximum safety and performance. Super-Lock Hub on all 5/8-11 threaded wheels is the safest, vibration-free design.