Canopy Air Professional Grade Pocket Air Filter, Moisture Resistant, Ultrasonically Welded Synthetic Media, White, 9 MERV, 3 Pockets, 24" Height x 12" Width x 22" Depth (Case of 4) Professional Grade Patented ultrasonic welding technology Open throat design for optimum air flow Galvanized steel header and J-channels for filter strength High efficiency filtration with low resistance to air flow Superior dust-holding capacity Made in USA