I ordered 6 of these and they work ok, but I have used others that were much better but cost as much as $16 each. I use them to transport beer samples to accounts for tasting, they allow me to keep appropriate carbonation levels between each stop. I've had others work better and worse than these. The issue is always with the poppet and seal inside, they don't always seat/seal and will leak the gas out (and beer if on its side). Sometimes you can push/pick at it to get it to seal but not before you lose most of the pressure. Just looking at the poppet you can see it's been ground to fit (rather than machined). The one I paid $16 for was much nicer and seals every time, not just 60% of the time. In this case it seems you get what you pay for. I thought I had bought the nicer ones from these guys, but maybe they got a new manufacturer.