Product review (5 stars): Exactly what I wanted
My disposal came with its own stopper and splash guard, but I wanted another so I could wash the stopper and get the gunk that collects on the bottom off.  This was perfect.  I'm VERY happy with it.

I read one review saying that it keeps coming out.  I have NEVER had that problem in the year and a half I've had my disposal.  Perhaps he/she doesn't push it down all the way?