This is a cotton 100% sheet custom-made for a Magniflex Mesh Wing semi-double mattress from Tsukuru Cover, a sheet specialty store in Kyoto. The sheets in photos 3-5 are the same type that were previously used. The fitted sheet has a deep pocket and elastic around the top and bottom, so it folds neatly without bunching up. When unfolded, it smooths out very nicely without wrinkles. I purchased this previously as a spare, but I didn't end up using it. 118 x 199 x 11cm