I have an American Standard 4114 Cadet that was installed in 2002. When I needed to replace the flapper, I went to the hardware store and bought a Korky flapper, which consistently got stuck open causing all the water to drain out of the tank. In a normal flush in this toilet, only about 1/3 of the water should drain. Despite spending a half hour on the phone with Korky customer service, verifying that that flapper should work with my toilet, and making adjustments, we couldn't figure out what the problem was, so the Korky person said she would send me a different flapper free of charge (she actually sent me two different ones, but I ended up not using either one). After looking at a lot of online reviews and plumbing forums, I saw that many people said they had the same problem using aftermarket universal flappers in AS toilets and recommended that only OEM parts be used. I still had the specs that came with the toilet when it was installed 13 years ago, so I got the part number for the flapper off that, but it turns out that flapper had been discontinued and replaced with this one. When I received this one, the packaging listed 16 different AS flappers that had been discontinued and replaced with this one. I presume they didn't have 16 identical parts all with different part numbers; evidently they used to have at least 16 probably slightly different flappers, and at some point decided to just go with one flapper for everything and this one was the result. They probably designed this to fit the largest number of AS toilet models and those of us without one of those models are out of luck. So how does it work? *Mostly* it works fine. It looks almost the same as the one it replaced, but the cup is a little shorter. Usually the toilet flushes normally, but every so often the flapper gets stuck in the open position and won't drop until almost all of the water has drained from the tank into the bowl. I've spent way too much time and wasted a lot of water watching what happens inside the tank when it gets stuck and there's no obvious reason. It's not catching on anything, the trip lever isn't stuck, water from the fill valve isn't holding it open -- it just won't close sometimes. (I know someone will say that since I had the same problem with both this flapper and the Korky that it isn't the flapper that's the problem. However, while I was waiting for this one to arrive from Amazon, I put the old leaky one back in, and it never got stuck open and it never had in the past either, so it does seem as if the problem is the flapper and not something else.) It seems as if each American Standard toilet model was designed to work with a specific flapper that they no longer make. This one might fit your toilet, or it might not. It might work okay most of the time, as it does with mine, but it should work all of the time. It's not worth it to get the plumber out just for this, but next time I call mine for something else, I'll probably have him take a look at this and see if he can figure it out. I do know, though, that given the choice in the future, I would not put in a brand of toilet that's so fussy about parts. I should be able to run down to the hardware store and pull a universal part off the shelf; having to order an AS part (because they aren't sold in stores except by special order) and then find that part is not a perfect fit is not okay.
