28x30x2 MERV 11 High Capacity (2 Pack) Geothermal Filter from Glasfloss Nominal Size 28" x 30" x 2" MERV 11 Exact Size 27-3/4" x 29-3/8" x 1-3/4" 2 Piece filter put together for strength Suggested change interval - every 3 months High Capacity - High Quality