J-Life Traditional Japanese Shiki Futon (Shikibuton) - TWIN SIZE with Custom Removable Asa No Ha Purple Cover 75" x 39"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).