3x3" (6 PANEL) Sold in sets of 3 identical books. Books have 4 images inside, 2 images outside. Custom Photo Covers are printed on Kodak Endura Lustre Paper. Designer Covers come with many different material options. All books are expandable and have a hidden magnetic closure to keep your book tightly closed. Semi-Gloss and Linen are the Standard paper options, while Pearl is your premium paper option.