Product review (4 stars): fit my old Tappan/Montgomery Ward perfectly
The rubber in my old (30? year) disposer had cracked and broken, and no local store had a replacement. When I had a plumber in for a different issue, he said he'd never seen one of these before (and he wasn't a young guy). I saw this on Amazon, and it looked like the size was right, so I bought it on a lark, since it was only a few bucks.

Well it fit perfectly. My only disappointment is that it tends to drain very slowly, although I suspect that will change over time.