... bearing durability. More size Model114, 126, 117, 127, 437, 517, 537, 617, 637,737,827 TypeTri-cone bits, Steel tooth ... 4" to 26" IADC 415,435,445,417,437,517,537,617TCI 437 soft formation tci tricone bitsThe 437 tci ... 118mm,120mm,127mm(5”)130.1mm(5 1/8”),133.3mm(5 1/4”),139.7mm(5 1/2”),142.8mm(5 5/8”),149. ... , 227TCI(IADC)415,435, 417,437515,525,535,545, 517,527,537,547615,625,635,,617,627,637,737512,522 ...