Features:* Drill Bit Usage: the cross cutting head can be suitable for the drill hole to easily penetrate the material (tile, glass) and reduce cracking. Note: Do not use this drill bit to drill thick cast iron plate and tempered glass* Dry-working alloy drill: traditional drill bit needs to add water to work, but this drill bit can directly feed the drill bit without adding water. (Use water for cooling when drilling. The drill bit will last longer)* New electrophoretic painting process: the drill bit adopts a new electrophoretic painting process, abandoning the traditional spraying process, processing anti-corrosion treatment, and making the drill bit more durable.* 1/4" hex chuck: the drill bit chuck design to the hex chuck, can fix more firmly on the drill * Unique transverse angle design: small incision resistance, stable drilling, speed, no breaking the limit. Opening neat, smooth, no broken edges, no shaking phenomenon, easy chips.* Wide Application: Professional glass and tile drill bits provide smooth and accurate drilling in ceramic tile, marble, thin iron, mirrors and glass. Be sure to add water or coolant when drilling. Specifications:Material: YG6X hard alloy Ball: Black Drill Holder: 1/4" Hex Shank Process: Electrophoretic PaintQuantity & Size:1 pc. 1/8" (3mm) Dia x 70mm(L)1 pc 5/32" (4mm) Dia x 70mm(L)1 pc 3/16" (5mm) Dia x 75mm(L)1 pc. 1/4" (6mm) Dia x 76mm(L)1pc 9/32" (7mm) Dia x 77mm(L)1 pc. 5/16" (8mm) Dia x 78mm(L)1 pc 3/8" (10mm) Dia x 83mm(L)1 pc. 1/2" (12mm) Dia x 87mm(L) Package Contents: 8pcs/set drill bit