Nominal size: 20x25x5; Actual size: 20 3/8"x24 1/4"x4 3/4"; This MERV 13 filter is comparable with MPR 1500-1900 & FPR 10 Replaces Air Bear part numbers 229990-103, 248713-104, 455604-001, 455604-019, 255649-102, 229990-102, 259112-102, and BestAir Pro AB-2025-11 Designed to filter microscopic particles such as lint, dust mites, spores, pollen, pet dander, fine dust, smoke, viruses, and bacteria Simple to install and a cost-effective step towards a healthier home environment. For best results, replace 3"-5" filters every 3-6 months but increase frequency to 30 days during peak summer and winter months 100% synthetic electrostatic media for high efficiency with low air flow resistance