Relax Mood mattress has Special HR (High Resilient) Sponge with Increased Density on both sides. One surface of the mattress has a hardness above the standard and the other surface has an extra hardness. Since the concept of hardness can differ from person to person, you can enjoy a comfortable sleep by using a surface with a suitable hardness for you. The Relax Mood mattress prevents excessive strain on the joints that make up the spine by keeping the body in the ideal position during sleep. It minimizes the pressure due to lying on the protruding parts of the body.