Steel head material with stronger hardness. Spiral shape design, operation more stable. Fine grinding of the drill body, big slot design, conducive to chip removal, to the tile wall. Easy to install, ordinary drill, drill can be installed, easy to carry and decorate. Wide applicability of glass, ceramic tile, marble, cement wall, plastic, wood, etc. Features - Color: Assorted color. - Material: Steel. - Size: 9.00 x 2.00 x 1.80cm/ 3.54 x 0.79 x 0.71 inch. - Very suitable for using to multi size wood hole drilling. One tool for multi uses, improve your working efficiency. - Compatible with drilling machines with chuck, for drilling in wood or wood flooring. - It is recommended to use the center punch to position before drilling, keep the drill bit Vertical to prevent the drill from bending or breaking. - Each drill bit in the set features high-speeds alloy construction with a surface coating for high hardness, strength cutting power. - Even more, thanks to its precision grinding inclined design, each bit ensures fast drilling with excellent chip removal. Package list: 1 x counterbore drill (2.8 ) 1 x counterbore drill (2.8 x 10) 1 x counterbore drill (3 ) 1 x counterbore drill (3 x 10) 1 x counterbore drill (3.2 ) 1 x counterbore drill (3.2 x 10)