Quickun 5/16" One Way Inline Check Valve, Non Return Hose Barb, Ozone Resistance Plastic Valve for Fuel Oil Water Gas Pump Air, 2 Pcs

These made the flow of the soap prrfect!

These are the real deal and they really work in your automotive windshield washer lines.

Haven’t gotten to use it in my system yet, but I tested the cracking pressure and it comes in at just over 2 inches of water column. I did have to push the inside open first with a chopstick to unseal it though. They should work for what I need. Will update if they don’t perform well.

Perfect for preventing backflow into the bucket of bleach from the backstream injector I use with my power washer. These are cheap but effective check valves for use with 3/8" tubing.

I needed a check valve between the fresh water tank and water pump in my RV. Hooking up to park water, through a pressure reducer, allowed water to overfill the tank and dump water out of the vent/overflow hose. Why Keystone didn't install one I'm sure was just saving a dollar hoping the pump diaphrams would suffice. I first did the "blow test", blowing thru these plastic valves one way and confirming I couldn't the other way. Both passed that simple test so I installed one. The first time I turned the pump on the valve "disassmbled" itself. I retrieved the pieces and spring from the hose and opted to not even try the other one, both returned.

These valves take a bit of pressure to open. they were not as sensitive to opening pressure as i needed. but they are quality pieces.

Of course, when you read about it being ozone resistant, one thinks this could be good for using on a spa to prevent back-flow from the ozone supply to the water injector. Sadly, one thing that's VERY difficult to obtain for this product, is the amount of pressure required in order for the gas to flow in the proper direction. With respect to a spa ozone maker, that amount of pressure it can produce is insufficient to cause this check valve to open. I bought the five pack thinking they would be perfect but for me, they're useless.

Bought these to allow excess crank pressure out of my crank case while also keeping any vacuum for necessary operation. So far I’ve only started the bike and let it run but have not gone for a ride, but it seems to be working as intended.

Were smaller than anticipated, but could be also slightly difference in pipe size

Great little valve

Check out my picture. The hours is 3/8" ID (see labelling on hoes). Compare to labelling of the package these came in and the one connected to the hoes. 🤨

Bateaux

Worked perfectly for my purpose. Only problem is that it's not marked which direction it should flow and a check valve only works one way. I just blew through each opening to figure out which direction would prevent air from going through before installing it.