I waited for quite awhile to write a review to make sure the product is still holding up. Its been almost 16 months and still going strong. I purchased this because during a recent bathroom remodel I did not have enough space to install a drain trap when I plumbed in a new shower pan. This guy did the trick to keep sewer gasses from filling the room. It more than keeps up with the flow from the shower. As others have said, you must get this shoved a good ways (3 inches or more) into the pipe so that the weight of the water will open the valve at the bottom. I have had to clean it twice since installation for hair clogs but once reinstalled it works as new. Don’t hesitate to buy if what you need it for is a shower drain.