I cannot find a fitting to work with this hose anywhere. It is certainly not NPT and no NPT fitting will seal or even go in more than a couple threads. It has an o-ring at the bottom. Nowhere on the internet does it give the actual type of threads. I think it might be 1/4" BSPP or BSPT, but I am not sure which and I am not for sure that is what it is. It could be something else. Harder & Steenbeck Braided Air Hose 6ft quick coupling-1/4"125883 https://spraygunner.com/braided-air-hose-6ft-quick-coupling-1-4/ This is the sole information you can find on Harder Steenbeck's website: "Braided hose complete, 2 m/6.3 ft (Item no. 125883) quick coupling nd 2.7 mm, connection 1/4" female screw thread" If anyone knows of a fitting that will allow my regulator to connect to this let me know. My regulator has a female 1/4" NPT hole. So I need a fitting or fittings combination that are 1/4" NPT Male to whatever this hose is. If I cannot find something I am going to have to machine my own which is a ridiculous waste of time. I am annoyed that I have wasted so much time already. Spray Gunner advised me to order a fitting from them that has no specs on what it even is and I am pretty sure it is just a 1/4" NPT Male to 1/4" Male NPT that I know will not work. https://spraygunner.com/1-4-male-straight-connector-by-no-name-brand/ Another place suggested a similar connector only theirs actually says it is NPT and I had them try it and they confirmed it does not work for them either. They said this fitting used to work for them and maybe it was tapered down farther at the end more before or something, but now seems to not work.....hmm. They at least test fit it after I suggested it may not work and that I already tried NPT.