Tier1 Replacement for Comfort Plus 20x21x5 Merv 8 Air Filter 2 Pack Rated at MERV 8 to capture particles 3-10 microns in size Replacement for: White-Rodgers F825-0586 and FR1600-100 Filter can also be used as a replacement filter for White-Rodgers electric air cleaner series SST16/SST1600 collection cell A811-0320/F811-0321 (Power must be disconnected when using a filter in place of a collection cell) This product is listed and rated by Underwriters Laboratories as U.L. Class 2