The custom-designed Super Center Innerspring unit is the secret to the comfort coil's dual benefits: Firm, healthful support like the best conventional and ease of flexibility which allows the futon to fold readily into a sofa. Four layers of super soft foam provide extra resiliency and long lasting comfort. Inside every comfort coil you'll find Gold Bond's custom-blended cotton batting- the densest and most durable in the world- using nothing but the purest 50% long-staple cotton picker and 50% cotton linter available. The box-like construction and heavy cotton twill outer shell give the Comfort Coil strength and durability.