Product review (1 stars): Not needed
This adapter is not needed if you are installing a Waste King disposal into a normal stainless steel sink.  In fact it is hard to imagine a sink, unless it were think granite, where you might need this adapter.  Everything you need comes in the box with the disposal.  The unit might be needed if you are installing the unit into an unusual sink that already has a three bolt fitting.  I recently installed a Waste King 8000 into a stainless steel sink and aside from having to cut the plastic outlet pipe and purchase a longer dishwasher pipe had no problem.

I ordered this adapter, just in case.  Amazon will of course take it back, but I must pay the return shipping cost.