About the XL Twin Otis Zone 3Enjoy the softness of this extra long mattress. This Zone 3 mattress is one of the softest made with pressurized high-density foam. Four layers fill in between the Belgian damask shell. The foam filling conforms to your b ody shape as you lie down. The fabric`s tailored edges will last for years. The exclusive Otis Comfort Lock Cushioning System tensions the material inside to create a consistent comfort level over the life of the mattress