... .Certified by ISO9001&API 2.Strong cutting structure durability 3.Fast drilling rate 4.Rubber seal or metal seal Place ... teeth all surface is are hardfaced strengthening, improved steel tooth shape and welding materials.Normal WOB KN/mm (bit ... ,12 1/413 3/4, 17 1/2,22, 24,26417 427 437517 527 537617 637 737Steel Tooth Tricone Bit3 7 ... /8 ,5 1/2, 6 1/27 7/8,8 1/2,8 3/410 ...