Nominal: 20 x 20 x 5 or 20x20x5, ac furnace air filter nominal size: 20 x 20 x 5, actual size: 19 3/4" x 19 7/8" x 4 3/8" comparable to filtrete mpr 600 dust reduction replaces honeywell part numbers: f25, 203721, f35, f35r, fc35a1019, f100, f150, fc100a1011, f200, fc200e1011, f50a1124, f50a1165, f50e1026, f50e1182, f50e6124, f50e6165, f50e8021, f50e8062, f50f1107, f50f1040, f55a1244, f55a1426, f55a1459, f55f1029, f55f1052, f58a1050, f58f1026, f300e1027 replaces lennox part number: x0585, x7930, x7935, hcc1423, hcf14-10, hcf14-16
