molten Sofia way Quoting from the following HP: It has a reversible (double-sided) structure with different firmnesses. You can use the softer front side and the firmer back side as you prefer. The head and foot areas gently support the body with small slits, and the back to thigh area prevents the body from sinking in with large slits, achieving both comfortable sleep and ease of turning over. Special urethane foam makes it less likely to "sag" with long-term use. Dirt on the mattress surface can be easily wiped off, and "sanitizing disinfection" with alcohol, etc. is possible. The product will be rolled up and sent in simple packaging. ☆