Product review (5 stars): Quick, easy, inexpensive replacement for my old Sinkmaster
Exactly what I was hoping it would be: a quick, simple, inexpensive fix to prevent unwanted items (spoons, cups, etc.) from ending up in the disposal.  The instructions on the box talk about removing the flange, or disposal, and greasing the ring or something like that.  It is literally as easy as taking it out of the packaging and shoving it down the disposal hole until it sits on the lip of the disposal.  It was a perfect fit for my sinkmaster disposal.