Malida 1/4" RO Water Tube Fitting Check Valve,Straight Quick Push to Connect Check Valve,for Ro Water Systems,Water Purifier, Pack of 5

Easy to use, no leaks so far. Probably get more than you need in case of failures, but I pretty lucky with my batch.

I purchased a set of these some years ago, and ran out recently, so I purchased another set of these. Yesterday, I had one decide to no longer let any water through it. I pulled it off and replaced it with one that is functioning correctly. On the off chance it wasn’t just this one, today I checked the rest of them that I have installed and found three more that were barely flowing. Of the nine that I have installed, four of them are not working properly.They work great when they work, but I really wish I could trust them.

I installed a ASO (Automatic Shutoff Valve) on my RO unit and noticed that the waste line on my RO continued to run even when the the RO tank was full. After some troubleshooting, I was able to isolate the problem down and discovered that RO membrane canister's built-in Check-Valve was faulty and allowed the filtered tank water to backfill into the filter and out via the waste line. Installing this one-way check valve on line that feeds filtered water from the membrane canister into the tank fixed the problem.

Well, I only needed one of these, to put in our RO water system - since the stenner tube fails annually, and then the tank overflows. so a check valve in the line to prevent the tank from overflowing made good sense (not sure why the installer didn't do this).... anyway - for the price - how could I go wrong with several of them. Anyway - now I have spares I suppose - but the one I installed is working great, and the slip fitting is awesome. literally took seconds to install this, and a huge problem solved.

Not sure why folks think they can build enough pressure to blow through these with their mouth, but as soon as I hooked it up the the waste water line on my RO system, it started flowing. Yeah, it takes SOME pressure, obviously more than one can blow with their mouth, but it's not too much if used with pressurized water, hooked up properly.

All five check valves did not work.No flow in either direction

We got these for our RO system because dad broke the one we had on it. He broke it by trying to twist the plastic tubing out instead of doing it the correct way. These are great, 5 pieces with locking clips. Dad had no problems replacing the one he had broken with a new one and then went around teaching us all how to remove the plastic tubing "Correctly* with the other 4. These were a good buy.

Fit my Watt system perfectly. And 4 left over to give as Christmas presents!