THESE CARBIDE BURRS ARE DESIGNED TO GRIND AND SHAPE ALUMINUM AND OTHER NON-FERROUS METALS. THEY ARE USED IN ELECTRIC, PNEUMATIC, AND HYDRAULIC DIE GRINDERS. THESE BURRS ARE ESSENTIALLY POWER FILES WHICH CAN GRIND IN TIGHT SPACES WITH PRECISION FOCUS. USED BY MECHANICS, MACHINISTS, TRADESMEN, AND HOBBYISTS.