Diablo, 4" x 0.040" x 5/8", Premium Metal Cut-Off Discs, Provides Superior Performance & Increased Productivity, Premium Aluminum Oxide Blend, Cut Through Material Faster Than Other Cut-Off Discs & Extra Long Cutting Life, Thin Kerf Design Provides For Thin, Fast Cut With Minimal Burr Formation, Fully Reinforced For Use In Hand Held Cut-Off Work, Ideal For Use When Working In Hard To Reach Areas.