... service 4. Good feedback of clients 17 1/2" tricone drill bit : size from 60mm to 26 inch,metal sealed ... with new formulas and new techniques for insert bit. Gauge StructureMultiple gauge protection with gauge trimmers ... Size: 6",6 1/2",7 1/2",8 1/2",9 1/2",9 5/8",9 7 ... 3/4",6",6 1/2",7 1/2",8 1/2",9 1/2",9 5/8",9 ... 4",15",15 1/2",17 1/2", etc. IADC Code:5-- Series,6-- Series 17 1/2" tricone drill bit