I work for a machine shop that specializes in couplings and threaded pipe, VAM Services is another company that runs specialized buttress threads for fracking known as premium connection. i know they have very strict tolerances and requirements for the manufacturing, shipping, and inventory of their "premium connection" couplings and tubing, if you know of GB Tubulars they are in a sense VAM "Light". if anyone has worked with them before i would like to know what to expect.