Product review (5 stars): Great design.
Moved into a house with an old InSinkErator, and the rubber flaps around the sink opening were all cut off.  I was worried I'd have to take the whole thing apart to replace the part, or maybe even need to get a new disposal unit.  But this thing just pops right in!  And it can come out for cleaning, or to get at anything stuck in the disposal. Great design.