Mattresses and Accessories - Drive, Inner Spring Mattress, 84" x 36", Firm : The Inner Spring Mattress by Drive Medical offers a high quality inner spring design ensuring you are at max comfort. The mattress has a vinyl cover that is waterproof, anti-bacterial, and anti-static for convenience and ease of use. The mattress is made of Premium Grade cotton and a high-density urethane foam for maximum comfort and increased durability.