... bearingaircooled bearing typeFormation or layer soft ,medium soft ,hard,medium hard,very hard formationButton size (extra features)Button bit,saw teeth1 ... bit,milled tooth , rock roller bit,tricone bit,tungsten carbide insert rock bit,tri-cone drill bit ,3 cone ... -9 1/2539-83360-40hardSandy, Shale, Quartzite, Hard Dolomite, Hard Sandstone etc.695.~-174.63 3/4-6 7 ... mm with 3 1/2" REG Pin for Hard Rock