1,bit API& ISO 2,bit size 8 1/2 215.9mm 3,bit iadc code 517 4,bit rubber/journal ... ”),158.7mm(6 1/4”),161.9mm(6 3/8”),165.1mm(6 1/2”)190.5mm(7 1/2”),193 ... ”),200.0mm(7 7/8”)212.7mm(8 3/8”),215.9mm(8 1/2”),222.2mm8 3/4”) 241.3 ... the layer.4)plz tell the quantity. 8 1/2 215.9mm iadc 517 tricone bit