Dial Indicators, Micrometers, Calipers manufacturer / supplier in China, offering Easy to Use API Spec 7-2 Conform Standard Internal Flush (6 5/8 IF) Thread Working/Master Gauges Quality Assurance for Drill String Components, Precision API Spec 7-2 Full Hole Pressure Gauge Petroleum Measurement Devices with Calibration Certificate, Oil and Gas Industry 60℃ Angle API Internal Flush (IF) 5 1/2 If Thread Gages for The Threaded Parts of Steel Pipes, Casing, Tubing and so on.