... the shirttail increases gauge holding capability and bearing life.3).Bearing Structure of this series tricone rock bit :High ... Abrasion resistance and seizure resistance of the bearing are improved and suitable for high rotary speed.4).Seal and ... L/C,Western unionDelivery termsBy sea or by airDelivery timeWithin 3 to 7 daysMarketCanada, USA,Middle east ,Africa,EuropeApplicationpetroleum&gas ...