FERRODAY Stainless Steel Carbonation Cap Forced Carbonation PET Bottle Filling 5/16 Barb CO2 Coupling to Carbonate Soda Beer Stainless Steel PET Bottle Carbonation Cap + O-ring + Gasket

These work well, better than the plastic caps. And they come with extra washers and o rings.

This is a good cap. I bought another that wasn't so good

I bought these for my wife since she got real big into sparkling water. I never realized that there was plastic in the aluminum cans. This was a way to reduce our plastic use and keep the amount of empty cans to a minimum.I chose this route over the soda stream for a few reasons. For starters I already had a CO2 cylinder with a ball-lock system due to home brewing with a cornelius keg. The other reason was for us to be able to reuse the sparkling plastic bottles that you can buy and be able to …carbonate any volume you would like. This does thread onto a standard plastic soda pop bottle thread so your container size is realy only limited to that.Another use of this over the soda stream is the ability to carbonate more than only water. Can carbonate iced tea or coffee too. You can also recarbonate a liquid after opening it. She tends to not finish her drinks and now you can repressurise the bottle and save it for later. For best results make sure that the liquid is cold first by ether having it in the fridge or place in the freezer for upto an hour. Do not let it freeze, or you will be very sad and have to wait for it to thaw.

Perfect fit for standard soda bottles and my CO2 carbonator filler gizmo. At first, one of the filler valves leaked a bit, but keeping the leaker pressurized for a while allowed it to seat reliably now. I tested each one by nearly filling a small soda bottle with cold water and gassing it up properly, then placing it on its side, with the CO2 cap over a dry paper towel, to look for slow leaks. These come with 2 spare bottle gaskets and 2 filler "snout" O-rings, but don't include the tiny rub…ber CO2 valve seals, which could be problematic. I'm assuming (hoping) they are tiny O-rings. Unscrewing the 5/16" center barbed tube should give access to the spring, valve body & gas seal. I believe this barb fitting was listed as 1/4" -it's larger, but 1/4" aquarium tubing fits inside the barb, if you plan to use an air stone to assist your carbonation speed.These appear well-built, but would be much easier to screw on & off of a bottle if the manufacturer had knurled the slippery rascal! Thin silicone sheeting ("Dicem") is the simple answer to fingers slipping on the smooth surface.They make a nearly empty bottle a bit top-heavy, but I expect they'll last forever, as they're built like a tank!A good product -- Cheers!

Bought two of these that we use on 2 liter PET bottles for making carbonated water. Have been using for a good 6 months now. No issues. Keeps good seal and pressure. Local homebrew and wine making shop didn't have anything that would allow you to hook up a PET bottle to a CO2 regulator. This is a godsend and has enable us to always have a supply of cold sparkling water on hand!

Great to carbonate bottles at a great pri, thanks!!!!

Out of four caps, three leaked from the connection to the ball lock disconnect. Discovered the installed o-rings on the leaking caps were smaller than the extras shipped with the caps. Once the larger o-rings were in place, no more leaks. An odd, but easily corrected, error. Excellent caps!

Since it has cutouts for a wrench, I cinched it down a bit beyond finger tight. It leaked a lot! When I backed off, it stopped leaking.I was screwing it down onto a plastic 2L adapter for a homemade fizzy water maker.Once tightened properly, it works like a charm! Doesn't leak when disconnected and barely any comes out when connecting the fitting.Nicely made! Good price!

This was easy to connect and has zero leakage. It’s perfect for home carbonation and fits any standard soda bottle

Don't -ever- buy the plastic one.The plastic one does not have seals, has a smaller opening, and is not threaded right.By comparison, this one -does- have seals, has a -larger- opening, and -is- threaded right.