Siliconized fabric with a smooth finish for easy packing. Oval base design for easy packing. Fully seam-sealed for maximum water-proofness. Reinforced stitching for greater seam strength on all stress points. The waterproof sack weighs less than 1.5 oz. and folds down to 1"x2"x3". So, even when full, it's remarkably easy to carry. Simply push out most of the air, then fold down the bag's top at least 3 times. Snap the buckle shut & you're set! Perfect for Ultralight Backpacking! If you're unhappy with this ultralight bag, send it back for a full refund of your purchase price. Love our Aquafree Ultra Light Dry Bag or your money back!