... ,11,12 degree taper).Bit diameter:28mm-57mm.3.Extension drilling toolsButton bit, face design :Flat face, drop ... 60mm-254mm bits with flat face, concave design fit for the atlas copco and ingersoll-rand ... of round cutter bit and flat cutter bits for excavate coal machine as the replacements of kennametal ... . Such as U76,U82,U84,U85,U92,U94,U95,U118 And coal bolting bit ...