HSS Titanium Coating - Classic HSS construction with titanium coating for greater capacity and durability. The cutting edge is hardened and honed for sharpness, chatter-free design with staggered cutting teeth ensures precise countersinking and smooth hole cleaning. Flute Shape - 2-flute shape helps clear chips and debris from the drill bit, reducing friction and heat for a faster and cooler drilling process. Quick Change - 1/4 inch hex shank fits all power tools more easily and securely, specially for locking into the quick change chuck. Meet Your Demands - Great drill bit set for metal/wood/plastic countersink. Suitable for home DIY and general construction/engineering use. Organized Holder - A drill bit holder with size index is included in the set for easy storage and organization. The drill bit set fits most brands currently on the market.