Water pressure reducer thread issue

[Retirednotdead]

Ordered this pressure reducer from Amazon a month ago. It was a couple weeks till I was able to test it at the next time out with our trailer. Surprise it didn't thread right on to the hose bib and sprayed water everywhere.
When I replied to the seller he said the thread was NH not garden hose which is what we use here in Canada and the USA.
They said to try teflon tape but the female connector has to screw right on to tension the fitting and the tape would do nothing. Leaked all over.
Long story short is I found the male and female fittings (not at the same store) and installed to the regulator. Works great now.
Don't know how they are marketing these toward RV community?