4 Foam mattress extension fills the gap when using an 80 mattress on an 84 . * Hook and loop fastener secures extension to mattress to reduce shifting. * Soft and durable zippered Chemsafe cover is bacteria resistant flame retardant fluid resistant anti-static non-allergenic stain resistant and easy to clean. * Meets 16 CFR 1633 requirements. * Not made with natural rubber latex.