Cobalt Drill Bit Set 7pce 1.56mmOverviewUltra-hard 5% cobalt steel. Use on alloy and hardened steel, cast iron, titanium and stainless steel. Always use cooling agent. Sizes: 1.5, 2, 3, 4, 5, 5.5 and 6mm. Loops 7 Piece 1.5mm 6mm Cobalt Drill Bit Set For Steel Cast Iron Titanium Stainless in Metallics