Product review (5 stars): Cooper is the best!
Much better built than the competition and less expensive too.  Cable clamp means that you can use this for an extension cord or a wall mount.  My application was to mate it to a crow foot plug as an adapter.  A ready made adapter would run $100 more than the components and this way, you know what you are using is built right.  Cooper stuff is easier to use because it has better engineering and construction.  The fact that it costs less is an added bonus and confirms the conclusion that using Cooper is a no-brainer!