Foster Fittings

I can say from my own experience... there are 2 basic styles, whether it's on purpose on not, its annoying. For me, it the length of the neck vs the collar on the male fitting. And maybe a corresponding difference in the female fittings. I'm looking for a pic I shared a for months ago, I'll update the post if I can find it.



Found it... top one won't fit anything I own. I buy both male and female fitting 5 at a time and always from the same vendor and I make sure they fit before I do anything else with them. 

They SHOULD be standard but I've had fittings that I've bought online that were either difficult or near impossible to connect until I ran some fine Emery cloth over the edges of the Male fitting. Just MY experience. 

Wanted to say, but forgot. Don't buy a whole new adapter for your CF tank before trying out a different Male foster or "sanding" it.

The Chinese fosters seem to have no rhyme or reason as for the sizes or length of the rings on the male fosters finding a pair that fit together is not as easy as it would seem. I used to think that if I bought them from the same seller that they would fit together NOT. These days I buy nothing but Ninja branded fittings as they always fit together and the quality is there.



I have tossed many that will not fit together with much of anything but kept a few just in case.

I too went through some frustrating times trying to get all of the different foster fittings to fit....and not leak. What I discovered is that most foster fittings we have here are 1/8 BSPP(British Standard Parallel Pipe), which are straight, not tapered threads. The Chinese typically use M10 fittings, not BSPP. They are almost the exact same size. A male 1/8 BSPP will screw into a female M10, but not the other way around. The QD(foster)ends are the same regardless of the threads.

Not sure if this is what the OP is having problems with...it’s just something that took me a while to figure out.

My opinion on this matter, buy the best you can afford. Don’t fall for ones just because the ad says made out of stainless steel. SS would always be a first choice, but buy from places like Best fittings, Air Tanks Plus, Ninja, Airhog, and the other quality vendors. They cost more, and that’s because you’re paying for quality. 

I tried the amazon or flea bay ones that come from overseas, and after one female QD let loose while filling up my tank with my Lightning, I decided no more overseas QD connectors for me. I know there are others this has happened to because I read about those events. 

whenever possible, I try to use fittings that thread onto the end of a fill whip, and the other end that connects to a tank is the female spin to thread fitting for scba tanks. It’s a solid connection, with no QD fosters to fail. For my Airhog tank that’s a DIN style I use one of these so I can attach the fill whip to it. Again, a solid connection

+1. Buy the best quality you can afford for HPA fittings. Seems like common sense safety.