This is a great all around mattress made either 7" 8" 9" thick using two pieces of convoluted "egg crate " type foam in the core of the mattress. This foam is of a medium to high density and works exceptionally well for a bifold sofa style futon frame as well as for a platform bed. The 9" thick is a great choice for those who plan to use the futon for everyday use or sleeping. This is an excellent multi purpose futon that has long lasting durability and comfort.