114mm 4 1/2" remet double-wall pole reverse circulation Product Description: The high-pressure air and the gas pipe are transported to somewhere in .....
41F Type Of Threads Or Customized As Required Double Wall Drill Pipe Product Description In order to realize the reverse circulation drilling process ...
Double Wall Rods Reverse Cireulation Drilling Pipe For Geological Research Product Description In order to realize the reverse circulation drilling .....