Sleep Comfort 4-Inch Memory Foam Topper with Waterproof Cover, California King 100% Polyester Made in US Gently cradles your body Breathable laminate backing material offers moisture control preventing fluids from penetrating the surface of the mattress topper Naturally hypoallergenic to provide a healthier sleep environment Reduces tossing and turning for a deep, healthy night's sleep Originally designed for NASA this space age foam cradles your body, reducing pressure points that cause tossing and turning