Tier1 Replacement for Trane 21x23.5x5 Merv 8 BAYFTAH23M Air Filter 2 Pack Rated at MERV 8 to capture particles 3-10 microns in size Replacement for: Trane BAYFTAH23M and FLR06073 Up to twenty times more effective than ordinary fiberglass filters This product is listed and rated by Underwriters Laboratories as U.L. Class 2