21x27x5 (20.7x26.2x5) MERV 13 Aftermarket Trane Replacement Filter (2 Pack) Trane Perfect Fit air filter #BAYFRAME21A, BAYFTFR21M, TFM210B0FR0, TFM210A0FR00, TFM210A0FR10,TFM210B0FR01, TFM210B0FR0A, and TFM21DA0FR00 Nominal size 21" x 27" x 5" Actual Size 20.7" x 26.2" x 5" 98% efficient filtration media This is an aftermarket filter.