Wool Topper: Consists of 2.5 inches of pure soft wool that provides comfort and support while encased in 100% organic cotton fabric. Attached firmly to the mattress with elastic straps, this wool topper can reduce tossing and turning by 50%. It fits mattresses up to 12-inches in thickness. Natural Rubber Topper: It is composed of a 2-inch natural rubber layer surrounded by layers of pure wool and a quilted organic cotton cover. This mattress topper improves comfort while naturally repelling dust mites. The Natural Rubber Topper is naturally resistant to moisture build up. It is naturally antibacterial and hypoallergenic. Mold and dust free.