toolant Pro Cobalt Countersink Drill Bit Set - An exceptional choice for Chamfering. Consisting of 5 titanium aluminum nitride coated cobalt drill bits, offers exceptional performance specifically for drilling through metal. Titanium Aluminum Nitride Coating - Increases surface hardness to 94HRC with outstanding heat-resistance, so your drill bit cuts fast and stay sharp Industrial Grade Cobalt High-speed Steel - Superior strength, heat resistance, and durability, making it ideal for drilling metal Impact Ready Hex Shank - One-piece built solid 1/4" Hex Shank for quick change 90 Days Warranty - In the event that you are not completely satisfied with your purchase for any reason, please reach out to us, and we will gladly provide a 105% refund or replacement. toolant Noir-Ti Cobalt Countersink Drill Bit Set(Pro), Titanium Aluminum Nitride Coated with Quick Change Hex Shank, 5-piece 1/4" - 3/4"