I purchased a shower system (made in China) from another big online retailer and was surprised to learn that NPT threaded fittings are only used in the US and Canada. The rest of the world uses BSP (British Standard Pipe). Well, I also learned that instructions translated from Chinese to English are not always crystal clear and so getting my new shower connected (there were 8 fittings) was a matter of trial and error because the shower diverter/mixer valves were parallel (BSPP) threaded and the devices (rainfall shower, waterfall, handheld) where BSPT (tapered). So I found these, which were perfect for my application, but again, due to poor instructions, it was a trial and error exercise figuring out what I needed. I ended up buying more adapters than I needed, and so I had to return what I didn't need. In the end, it all worked out, but next time, I'm buying an American brand (probably also made in China, but at least to US standards)