True HEPA Filtration removes 99.97% of airborne allergens from the air that passes through the filter. Arm & Hammer enhanced pre-filter for odor control. Progress Bar: Green LED: Filter is working effectively. Yellow LED: Time to purchase a new filter. Red LED: Time to replace the filter. Digital display with auto off timer. Recommended for medium rooms, up to 299 sq. ft. Smoke CADR: 193. Filter: 2 x HAPF600M.