Oatey 42725 Backwater Valve Device, 2-Inch

Fits my 1940's basement floor drain "P-Trap drain" just perfectly. Finally got the old one out and this dropped in like a charm. Be aware the rubber rim is thin and not robust material. The seal, when I originally installed it, was very good. However... I tried to lube it up with WD40 after it was installed, thinking that might tighten the seal, since it did upleak a tiny bit when my washing machine is trying to force-feed a tub-full of water down the basement drain (only enough to very slightly fill the drain's cup). However the WD40 corrupted the rubber, causing it to buckle & crinkle and therefore it started leaking way too much. I then tried Dupont Silicone spray, which is supposed to be safe on rubber. I guess it was the volatiles used in the spray delivery, because it buckled again and I had to replace it with a fresh one. Which, thanks to the low price of this item, is not painful. It would be nicer if this had a nice big faux-rubber "O" ring that could withstand some crap instead of a thin, obviously real-rubber skirt, but as long as I don't do anything stupid, I think the seal this provides is solid enough, and will hopefully last a while. Make sure to pair it with a water-leak alarm just in case ;) P.S. Yes my antique cast-iron 1939 version of this ball valve was difficult to get out... it was rusted in there good. Finally the light bulb came on, and I grabbed my sawz-all with a metal-cutting blade and cut a little chunk out of the old collar, after that I was able to chisel it loose and unscrew it. Just don't go deeper than necessary with the sawz-all to avoid damaging the threads in the female portion of the drain in the floor. Hope that helps -- it only took me 14 years to figure out how to get the old one out!! :)

I am a contractor, I bought this thinking it would work, for the life of me I could not figure out what it did or how it worked, sent it back to Amazon

Easy peasy. You put it in your floor drain, it stops back flows during storm surges etc. Hasn't been through a big storm yet but looks like it should work in theory.

These work in our home basement floor drains. However, the rubber skirt shows buckling and failure to seal, at about the 3 year mark. Be prepared to replace these every 3 years :(.

Worked perfectly to fix my basement floor drain that would sometimes drain slowly. I was poking around with the old valve and it seemed like it was getting stuck closed sometimes. I found this, took the old one out, put this one in, and it drains very nicely now. It's a standard design, but still a little akward to remove or install. Google said to use a cold chisel, but I ended up using a small bolt held in the center with vice grips. That allowed me to apply pressure on both sides at once and worked quite well.