(1) Top side: 100% polyurethane. (2) Underside: 100% polyester. (1) Liquid impermeable fitted cover to protect the mattress. Highest level of hygiene as mite, virus, pollutant, bed bug and bacteria proof. Suitable for allergy sufferers. Can be disinfected with commercially available disinfectants. (2) Breathable. Suitable for mattresses up to 17 cm height. Flame retardant according to BS 7175 Crib 5.