1.Reliable bearing system 2.Fast drilling rate 3..size rang from3"1/2-26" 4.Certification: API & ISO9001 5.delivery ... on time Type6"(152mm), 6 1/2"(165mm), 8 1/2"(215 ... 5/8"(371mm), 15"(381mm), 17 1/2"(445mm), 24"(609mm), 26"(660mm)IADC 147,437,447,517,527,537, ... 537 547 516 536 535available sizes:From 2 7/8 to 26”larger sizes for hole opener bit ,reamer ...