Features:* .* materials . It is made of YG8 alloy as raw material. The process of oxynitriding of the cutter head strengthen the drill hardness.*UNIQUE CROSS ANGLE DESIGNSmall incision resistancefeature drilling stably, fast speed, not breaking the border. Opening neat, smooth, no broken edges, no tremor phenomenon, chip easily.*WIDE USAGEProfessional glass and tile drill bits provide smooth and accurate drilling in ceramic tiles, marble, thin iron plate, mirrors and glass. Remember to add Water or coolant when drilling.*5 DIFFERENT SIZESSuitable for your different needs. It Can be installed in the general electric hand drill, bench drill. The machine drill clamp range is 10mm and above. Specifications:Material: Cemented CarbideColor: As picture showSize: 3*70mm, 4*70mm, 5*76mm, 6*77mm, 7*80mm,8*80mm ,10*83mm,12*83mm(Approx.)(optional)Package Contents:1*Universal Drilling Tool