... 1)certified by ISO9001&API 2) premium tungsten carbide insert 3)Durable bearing and cutting structure TCI Tricone bits: 1 ... durability of premium tungsten carbide insert is improved with new formulas and new techniques for insert bit.2)Multiple gauge protection ... specializes in drill bits, drill pipe, Mud pump and stabilizers for water well, oil field, construction, geothermal, directional boring, ...