A2Z Ozone 856689005191 Check Valve, 1/4 inch

Seems to work fine... I can not conceive of giving this type of item more than 4 stars due to its nature. It works, I have not had any issues, and it is functional. It does not astound me in anyway, shape or form, but it does its function well. In the land of only having the potential to get 4 stars, it gets those 4.

I bought this to go with an ozonator I ordered on Amazon, only to find out it came with one anyway. Not worth the trouble to return.

Two to a package. Works just fine. Be sure to blow into it to figure out the proper direction.

Excellent replacement for my ozone tubing on my Hotsprings Vista spa. I went ahead and replaced tubing at the same time. Snug fit on a 1/4" tube. Comes in a two pack, now I have a spare. I have never replaced this before and I bought my hot tub in winter 2006, I read online you should run 8oz vinegar through the line once a year, never had but now I know, hope it helps someone else. Lasted 9 years now has a new one on and a spare in the tool box, good to go.

Small valve, but appears to do the trick

Slightly smaller than expectec but is working well.

I tried to use this in my spa on the ozonator line. Please note that ends are not barbed so this unit does not seal well and if there is a water back flow, it can pop out of the ozone tubing. Unit also did not stop backflow of water, just slowed it.

works great.