*The Minimum Efficiency Reporting Value (MERV) of this filter cartridge has been determined through independent laboratory testing using ASHRAE 52.2 (2007) test standards. The MERV rating was determined at a face velocity of 36 meters per minute / 118 feet per minute and loading up to 101.6 mm / 4 in. water gauge. Actual efficiency of any filter cartridge will vary according to the specific application parameters. Dust concentration, airflow, particle characteristics, and pulse cleaning methods all affect filtration efficiency. MERV 15 available in U.S. only.** Based on clean filters.†Magnehelic and Photohelic are registered trademarks of Dwyer Instruments, Inc.