... global sale 1.OD: 2 3/8", 2 7/8", 3 1/2", 4" ,4 1/2", 5", 5 1/2" , ... Feature Ⅰ HW Drill Pipe by welding—OD 3-1/2“to 5-1/2’ tool joints made separately sufficient heat ... line with NS-1requirement. Proprietary product——Tool Joint 1.DPDS——Double Shoulder Tool Joint Developed by DP-Master ... DP-Master's Advantages Strategic partnership with Tuboscope 1)Quality Control-Tuboscope Inspection on all New Drill ...