Norton Toolroom Wheel, Flaring Cup, Series: 5SG, 4 in Wheel Diameter, 1-1/2 in Wheel Thickness, 1-1/4 in Center Hole, 46 Grit, Medium Grade, Ceramic Alumina Abrasive, 5730 rpm Maximum, Wheel Hardness: K, Vitrified Bond, Applicable Materials: 400 Series Stainless, Hard Carbon Steel, Tool Steel, Titanium, Super Alloy, Cast Iron, Ductile Iron and Gray Iron, Blue Wheel, Wheel Type Number: Type 11