... 3.Water Hole: 2 4.Body: Normal Taper Drill Bits Rock The Advantages Of Taper Drill Bits Rock1. Higher Quality2. With Strict Quality Control3 ... . More Reasonable price4. Better After-Sales ServiceThe Taper Drill Bits Rock are made from grade hard alloy and special steel ... :4.8,6,7,11,12The diameter for taper:15,19,22,24,25(mm) Drill TypeBit diamater (D)TaperWhter hole(d ...