The Stratus Futon Mattress is one of our most popular futon mattresses giving the same feel you would expect from a traditional Innerspring Mattress. A 4 Inch core of double-tempered high strength steel innersprings are surrounded by 2 layers of high resilience eco-friendly foam to add more cushioning. These layers are encased in several layers of blended cotton. The top and bottom layers are identical making this a flippable mattress. The Stratus Innerspring Mattress is on the softer side and recommended for side sleepers on a futon sofa bed frame. The Stratus Spring Cotton Futon Mattress is perfect for any occasional use futon sofa sleeper or convertible futon frames.