Outside Propane Connection??

Thanks for the info. Does the Extend-a-Stay fasten to the fixed tank (inside the BIG door), or does it plug into the propane connection on the little door (that is ONLY a propane connector...nothing else in there). And where do you purchase this? I've done searches, but can't find a product called "Extend-A-Stay", although the search engine says it exists. Amazon links to tee-adapters.