Features: The Spyder Bite 4.5 in. Aluminum Oxide Grinding Wheels provide fast cuts and quick material removal on mild steel, stainless steel, ferrous metal and cast iron. A reinforced design yields more fast material removal on battery-operated tools and provides extended performance on higher torque plug-in tools. There are 3 wheels included per pack. Premium aluminum oxide abrasive provides fast material removal and long service life Type 27 depressed center-profile for offset grinding and flush cuts 7/8 in. arbor Contaminant-free construction meets INOX requirements and contains 0.1% or less of iron, sulfur, and chlorine For use on angle grinders (13,300 RPM max.) to remove mild steel, stainless steel, and various other metals 4.5 in. diameter, 7/8 in. arbor, 1/4 in. thickness, Type 27 depressed center profile