Product review (5 stars): To bad I didn't think of this
A great fit in my inskerator 555 series disposer.  cut out the old original rubber flaps that are falling apart.  Snap this in from the top.  No plumbing or tape or nothing.  Seems to hold just fine.  1 second install.  Quieter than the original and seals better to keep the smells from coming out.  Get it.