... service 4. Good feedback of clients IADC 517 537 8 1/2" tricone bit : size from 60mm to ... 2",7 1/2",8 1/2",9 1/2",9 5/8",9 7/8",12 1/4",17 1 ... 1/2",7 7/8",8 1/2",9 1/2",9 5/8",9 7/8",12 1/4",14 3 ... Main Type AvailableSize: 8 1/2",9 1/2",9 5/8",9 7/8",10 5/8",12 1/4", etc. ... 2",7 1/2",8 1/2",9 1/2",9 5/8",9 7/8",12 1/4",15",15 ... 1/2",17 1/2", etc. IADC Code:5-- Series,6-- Series IADC 517 537 8 ...