Made of high quality cemented carbide Good performance, making clean and accurate holes for you A set of glass drills that are very easy to work with Small incision resistance,feature drilling stably, fast speed, not breaking the border Opening neat, smooth, no broken edges, no tremor phenomenon, chip easily Professional glass and tile drill bits provide smooth and accurate drilling in ceramic tiles, marble, china, mirrors and glass Cross tip design reduces breakout and the bit features a carbide tip for extended bit life Using Caution:Remember to add water to the materials while cutting or drilling to preserve them from over heating Wide Fit: Can be installed in the general electric hand drill, bench drill, impact drill and so on The machine drill clamp range is 10mm and above color:silver+goldSize:Shank diameter:3 1mm, 4 0mm, 4 3mm, 5 3mm, 6 9mm, 7 7mmCutter diameter: 4mm, 5mm, 6mm, 8mm, 10mm,12mmTotal length: 65mm, 69mm, 72mm, 77mm, 81mm, 85mmPackage Included:6 x Drill bitOnly the above package content, other products are not included Note: Light and different displays may cause the color of the item in the picture a little different from the real thing The measurement allowed error is +/- 1-3cm