This German-made one way gas check valve features 1/4" threaded flare fittings, to fit standard threaded ball and pin lock gas connectors. Prevents beer from backing up into gas lines. This releases at 3psi, and is a great way to add a one way valve to your threaded ball or pin lock keg connector.
Note: These should not be disassembled, they can be very hard to put back together, and replacement parts are not sold individually. Click on the 
for a pdf of the assembly diagram.
This shows the Keg Gas Check Valve screwed onto a ball-lock keg connector.
Nov 22, 2020 by Michael
Q: What materials are any parts that would potentially contact any liquid made from, i.e: stainless, plastic, plated brass, etc.?
A: Plastic and stainless parts are inside. This valve should keep beer out, and if it becomes full of beer, it should be replaced.
Aug 17, 2018 by Mike
Q: Can these be disassembled and/or cleaned?
A: Not recommended as replacement parts are not available, and they are very hard to put back together in the correct order.
Feb 18, 2018 by Edward
Q: Your description says it is a gas-side check valve. Is this also suitable for using on the liquid side of the keg, so one can force carbonate through the dip tube on the beer-out side? The liquid side gives more CO2 contact with the beer over time.
A: It should work fine on the liquid side, as long as beer does not contact the check valve.
Oct 24, 2017 by Bill
Q: I use a hose from the dip tube to the bottom of the keg with a carbonation stone on the end. Should this check valve keep the beer from coming into my gas line ? I bought 2 and I am getting beer in the gas line. Do I need to remove the tube with the stone
A: We are not sure why this is happening, do you know what the pressure in your keg is when this occurs?
Oct 16, 2017 by Zack
Q: Does this allow gas flow in both directions? Or does it only allow gas flow in a single direction while preventing both gas and liquid flow in the other direction?
A: This only allows gas to flow in one direction.
Excelent
Is perfec, thank
High quality in-line piece
I can't say I've experienced backflow, but looking into my keg coupler, the thing prevents backflow is a flimsy piece of silicone or something similar. So if this keeps any issues from occurring and dirtying my gas line, I'm all for it at the price point.
Must have
I have a 4 tap system and because I force carb I was getting beer back into my gas lines which over time made the lines skanky. When I rebuilt the gas lines I added these as $10 x 4 is cheaper than the time it takes to rebuild the lines. I wish I had thought about these when I built my keezer. Love Williams Brewing, always great service.
Quality Check Valve
I have found this to be very effective in preventing liquid into the gas tubing. However, my only issue is since it is a pressure release...it does not measure the pressure in the keg as well as a non check valve system. An issue I wish I knew prior to ordering.
Must have in kegging
I can't count how many times I was force carbonating, and beer goes back into the CO2 line. This solves the problem. The key is this check valve goes right on the ball valve, so there isn't a way for liquid to come out of the gas line. I had one at the regulator, and with enough pressure liquid still creeps up. I have another one that works, but since this is clear you can verify that you aren't having any seepage! Great product!