Product review (4 stars): it will just pop-off as you try to install fully - its sorta like putting a bike tire on
The product arrives in a large box, with absolutely  no instructions.  You will need to have youtube ready to install this bellow (or boot as its referred to).

The key to installing this product is to install the inner ring first, then install the outer ring. it took me over 1 hour to finally figure this out. If you try to install the outer ring, it will just pop-off as you try to install fully - its sorta like putting a bike tire on, but you can't force it as it may damage the rubber.

Install the inner ring first and the outer ring will go on much easier.