21x22x1 (20.5 x 21.5) AccumulairA (R) Diamond 1-Inch Filter (APR 1950)

AccumulairA (R) Diamond MERV 13 More than 30 times more efficient than ordinary fiberglass filters Highest efficiency AccumulairA (R) filter on the market Meets criteria required for certification in the Leadership in Energy Environmental Design Lasts up to three months