BACK HEALTH - These futons are somewhat thin so you do not sleep on a fully padded surface. You are sleeping on a firm surface which aligns your spine that leads to less back pains and less back problems. COMFORTABLE AND PORTABLE: The traditional Japanese futon mattress is also called Shiki futon and it is very comfortable to sleep in, despite being thin layered. It can even be used as a yoga or meditation mat since it can be folded easily. Since it is also lightweight you can pack it and use it for traveling, camping, and outings EXPANSION - Please allow this Shikibuton 3 full days minimum to expand completely. Seeing that it is packed air tight, it needs some time come around to full form and size. SPECIFICATION: The exact dimension of the mattress is: 39" x 83" for Twin-Long 55" x 83" for Full-Long 63" x 83" for Queen-Long The fabric is 100% organic and natural cotton, highly durable and soft material that's very easy to clean and has no offensive smell.