... 131, 211, 537, 517….4 1/2 211, 121, 241, 537….4 3/4 131, 211, 537, 517….5 1/2 131, 211, 537 ... 241, 537….……….. ………………………………12 1/2 211, 121, 241, 537….14 3/4 131, 211, 537, 517….15 1/2 211, 121, 241 ... , 537….17 1/2 131, 211, 537 ... 241, 537….………..………………………………26 131, 211, 537, 517…. API standard 12 1/4''steel tooth tricone bi for water well or oil well ...