With those keywords, I got a whole lot further, thanks man, indeed they're 5/8" both the 300 and 200bar .. 5/8" 18UNF to be precise (18 UNF??). I know I know, it should be illegal to be this noobish, I am a computer guy by day ... Im getting there. I am looking at this "Non regulated 7/8-14UNF"...