This filter measures 19x25x4 (18.5x24.5x3.75). Economical, high-capacity media makes this filter an ideal upgrade from standard fiberglass throwaways. Captures a wide variety of airborne allergens including dust, mold, pet dander, and dust mites. This filter is rugged and durable. It will not warp or leak under normal operating conditions. Up to 8-times more effective at capturing micro particles than ordinary fiberglass filters. Excellent for high-velocity systems and maximum air flow. Lasts up to 3 months.