About the XL Twin Otis Zone 9You will enjoy comfortable resilient support from this extra long mattress. Combining foam layers that are high density and contain latex properties this mattress is supremely comfortable. Its Belgian damask shell also ad ds comfort.This mattress conforms to your body 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 o f the mattress