... 3. Quality products & good service 4. Good feedback of clients 17 1/2" tricone drill bit : size from 60mm to 26 ... /2",9 5/8",9 7/8",12 1/4",17 1/2", etc. IADC Code:4-- Series, 5-- Series, 6 ... /8",9 7/8",12 1/4",14 3/4",17 1/2", etc. IADC Code:4-- Series, 5-- Series, 6 ... ",9 7/8",12 1/4",15",15 1/2",17 1/2", etc. IADC Code:5-- Series,6-- Series ...