Features: brand new and high quality Groove form: 2 groove forms help to remove chips and debris on the drill bit, reduce friction and heat, and achieve a faster and colder drilling process. HSS for Titanium Coating: Classic HSS structure with the ability and durability of for titanium coating. After quenching and honing, the cutting edge is for sharp and non-chattering design. The staggered cutting teeth ensure precise countersink and hole smoothness and cleanliness. Organized holder: The set contains a drill holder with a size index for easy storage and organization. Quick change: 1/4 inch hexagon handle is easier and safer to install in all power tools, specifically for locking into quick change chucks. To meet your needs: an excellent drill set for metal/wood/plastic countersinks. Suitable for household DIY and general construction/engineering purposes. Specifications: DIY Supplies: Woodworking Material: High Speed Steel Type: Twist Drill Size1: Approx.3mm/0.11inch Size2: Approx.4mm/0.15inch Size3: Approx.5mm/0.19inch Note: 1.Please allow 1-2mm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 15 PiecesxTwist Drill