An E-1 average size is 173 sq ft. with a 47 sq ft. balcony. There are designated E-1 cabins that will accomodate a third person. A D-1 cabin average size is 202 sq ft. with a 50 sq ft. balcony. Again, there are certain D-1 cabins that can hold 4 people, not all of them. You have to ask for them. A quad has a pull down bunk hidden in the ceiling. You will find both E-1 and D-1 on decks 6,7,8,9, and 10 on the Voyager class ships. I booked a quad and a triple for my Dec. 9th cruise on the Voyager of the seas. We got the third and forth person for only $10 each. It was a special we couldn't pass up.