Sleep & Beyond Dual Wool Mattress PadsThe reversible natural wool mattress pad has a very comfortable . 75 exposed wool pile top, unbleached, and a 100% Cotton 13. 5 oz back. Wool fibers trap air and have a natural elasticity so that when you lie down on the pad, your body will be cradled and supported without pressure to acupressure points. Wool wicks moisture away from your skin and helps maintain dry comfortable body temperature in hot and cold weather. Allergy sufferers love them.