complete in specifications drilling joints in diameters of 68/78/105/121millimeters
API SPEC7-1standard

complete in specifications drilling joints in diameters of68/78/105/121millimeters

plated with nickel phosphor that can increase the hardness and airtightness of the thread surface.

before plated and packaged,a series of tests have to be implemented including hardness,metallurgical structure,physical performances,etc.