... to establishing relationships with you in the near future 1,Structure features:1) Material: 15CrNi4MO2) Rubber/metal sealed bearing3) Jeurnal/ ... medium,medium-hard drilling information 6) Bit size:8 1/2"IADC code:5372,products details 3,Packingor steel box4 ... 10 5/8”),295.3(11 5/8”)311.1(12 1/4”),346.0 (13 5/8”),349.2(13 ... of the layer.4)plz tell the quantity. 8 1/2 215.9mm iadc 517 oil field drill bit