Norton Gemini is a good choice for steel and ferrous metals as well as specialty applications in aluminum and foundries. MSDS Sheet Features: Quality aluminum oxide Consistent performance at a competitive price Application: For heavy-duty to light grinding on the bottom/face of the wheel Specs: Abrasive Type Cut Off Wheel, Grinding Wheel Diameter 4.5 in Arbor 5/8" - 11 Thickness 1/4 in Wheel Type Type 27 Depressed Center Material Aluminum Oxide Specifications DC4514HGSS Trade Name GEMINI« RPM [max] 13580