... almost all IADC codes . 2.Rapid delivery time 3.Meet with API Spec7-1 Standard tricone bit, ... has good gauge protection and up drill capability. 3.Bearing StructureHigh precision journal bearing. Balls lock the ... it can receive higher WOB and high reliability. 4.Hydraulic DesignSmall angled watercourse design increased the shirttail ... 537,6174 5/8117.5517,527,537,6174 3/4120.6517,527,537,6175 7/8149.2517 ...