... many years. Including of tapered button bit, retract button bit, thread button bit.With ISO certificate & quality control.Button bits with 6tips, 7tips, 8tips, ... types: A. Taper button bitTapered button bit(28mm, 30mm, 32mm, 33mm, 34mm, 36mm, 38mm, 40mm, 42mm, 44mm and so on. With ... button bit (33mm, 35mm, 45mm, 51mm, 57mm, 64mm, 70mm, 76mm, 89mm, 102mm, 115mm, 127mm and so on. R25--38mm, R25-- ...