(1) Top side 100% polyester (silk jersey). (2) Underside polyurethane membrane. Weight approx. 160 g/m². (1) Protective covers protect your mattresses and prevent costly mattress cleaning. Protects them from contamination. Breathable. (2) Protects against liquids, mites, bacteria and allergens. All-around elastic for easy covering. For mattresses up to 25 cm height.