J-Life Traditional Japanese Shiki Futon (Shikibuton) - FULL SIZE with Custom Removable Seikai Ha Navy Cover 54" x 75" x 4" Traditional Japanese Futon - a true Japanese style mattress. Removable, washable cotton cover in one of our authentic imported Japanese fabrics. 5-Year Manufacturer's Warranty on Futon Cotton Mattress - no foam, wool, or innersprings Made With a Durable 100% Cotton outer material (unbleached).