... for Oil Well 20years experience in drill bit supply API&ISO9001 certification. API Kingdream Steel Tooth Tricone Bit for Oil Well Steel tooth ... protection with gauge inserts on the gauge surface of the cone, tungsten carbide inserts and hardfacing on the shirttail increases gauge ... /8 131, 211, 537, 517….4 1/2 211, 121, 241, 537….4 3/4 131, 211, 537, 517….5 1/2 131, 211, 537 ...