... products & good service 4. Good feedback of clients 17 1/2" tricone drill bit : size from 60mm to 26 inch,metal sealed and Elastomer ... .Main Type Available Size: 6",6 1/2",7 1/2",8 1/2",9 1/2",9 5/8",9 7/8",12 1/4",17 1/2", etc. IADC Code:4-- Series ... 1/2",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 17 1/2" tricone drill bit ...