Thirteen-inch cubes hold about forty percent more than the standard 11.8 in size, which is more than the extra inch on each side suggests. That difference is what decides whether a box takes folded adult jumpers and bed linen or is limited to children's clothes and small items. Double handles are what make a box this size manageable. A 13 in cube full of linen is heavy and bulky, and bringing it down from a shelf one-handed means tilting it, which sends the contents to one end. Two handles bring it down level and under control. Each box carries 11 lb and construction is 2 mm thick cardboard with 80 g non-woven fabric. The card thickness matters more at this size than at smaller ones, because a larger panel bows more easily, and it is what keeps the sides square when the box is loaded. Total weight is 8.8 lb. The boxes fold flat when not in use, so the ones you are not currently using store behind a wardrobe rather than sitting empty on a shelf taking the space you bought them to create.