Internal Backwater Valve,4-F 4" Float Model Flood-Guard for 3-inch Flood Drains,Drain Backflow Preventer for Sewer Flood Protection

A+. I deal with basement back ups when the city streets flood. Sump pump is fine, storm sewer is issue a backflow valve in the yard would cost thousands to install. This worked great so far in my basement. Last time I would’ve had an issue it barely let any water seal past the gasket edges. Usually I’d have 2-4” in the basement under these circumstances. I can probably tighten it a little more again, but it was very tight to begin with. Hold it with 1 hand and start screwing the 4 screws in a circle. Once snug you can crank it tight. Lean edges as best as possible. Mine was cast iron so hard to clean. Fit well. Works well. Also best one I’ve seen to allow water to go in, and not clog it up.

Everything else I could find for this size range is simply not performing up to the expected degree. This one does the job and does the job well

I purchased the 3" version and it fit perfectly. I saw reviews saying they could not control the water going down. There is nothing to adjust really on this. The 4 screws around makes the rubber expand the form a solid seal inside the pipe so that it cannot just be pulled or pushed out. The middle screw should not have to be adjusted. The water goes down with weight. If you have a cup of water it will not go down so press the button and down it goes but if there is a bucket, the weight pushes it down and allows it to drain. Hope this makes sense. For me, it works perfectly and what I needed. I installed one in a garage drain and now will order a second for the laundry room drain. Depending where you are and your situation, you could use these instead of putting a main one where you will have to dig. In my case there are only two small drains in the basement so it makes sense.

Solide et facile d’installation J’ai du réajuster la sensibilité mais tout semble parfait

This is excellent. I replaced one that I had for years but corroded. The key to using these is to put it down into the PVC tube just far enough that the center "pin" sticking up is about 1/4 inch below the level of the floor. This is made well, is a quality item, and is easy to install. I may buy another one so that in 20 years when this one is all nasty, I can replace it easily.