The Nat-Lux Optimum Pillow uses premium latex fill encased in a pillow liner cover in organic cotton with Joma wool batting. Wool creates the optimum batting to pad a pillow, regulating tempature and transporting moisture, and is antimicrobial, hypo-allergenic and resistant to dust mites. The pillow liner allows the latex to be added or removed to adjust the firmness of the Optimum Pillow and the fill can be shifted to get that "just right" feel for individual sleeping styles.