So Mike,

The answer to the question from a Mr. Carlos R. Lewison of Monster is thusly," Because some sub-woofers have a R & L input as do some receivers have a R & L sub-out." -This is the entire reply to my question. Kinda annoyed me and I think I'm going to reply to it

I guess the adapter is to y together the outputs from the reciever to the sub. Which is only a touch confusing because the photo of the interconnect at Crutchfield shows clearly shows it being used on the subwoofer which still makes no sense to me.