What are the exact functions of the advanced key on the 2006 audi a6?

someone told me that it has this thing where you can have it in your pocket/purse and lock/unlock your doors just by touching them, but it doesn't have that little square on the handle to lock it, thats what i see on most cars. so can someone please tell me what it does?What are the exact functions of the advanced key on the 2006 audi a6?All details are on their home page.