M1-1056 MERV 11 Replacement Media Air Filter for Series GMU/GBB Size 16x25x5 (Actual size: 15 3/8" x 25 1/2" x 5 1/4") Nominal Size: 16" x 25" x 5" Actual Size: 15-3/8" x 25-1/2" x 5-1/4" MERV 11 (ASHRAE 52.2), High Dust Holding Capacity Extended Service Life and Low Energy expenditures