Product review (4 stars): Awesome, The best (but sharp if you are a cleaner)
Love it!
Oh my gosh, the stopper that came with our disposal was horrible, it often flipped over, and we needed pliers to get it unstuck.
This is perfect for letting many of those icky things go down the drain, yet stop up the water when we need it.
I would have given it five stars, except: To clean between the second level in this picture and the bottom portion, it is sharp.  I have bigger fingers for a girl, and I managed to give myself a little cut (like a paper-cut on the top of my finger).  So be careful if you need to clean the nooks and crannies.  I love to have a spotless sink, so I have learned that I need a toothbrush to get in there and give it a good cleaning.
I would recommend it for anyone with a garbage disposal.
As for fit, I measured it before I received it.  I know that there are different sizes, so please take that into account.