Tier1 401 Comparable Replacement for Aprilaire 401 Air Filter Model 2400 DESIGNED TO FIT: Aprilaire Air Cleaner Models 2400 ACTUAL SIZE: 15 3/8 inches (length) x 26 15/16 inches (width) x 6 inches (depth) HIGH EFFICIENCY FILTRATION: Merv 11 Rating to reduce airborne particles like dust, mold spores, pollen, pet dander, and more EASY & QUICK INSTALLATION: Collapsible media designed to ensure easy installation 100% TIER1 NO WORRIES GUARANTEE - We stand behind the quality of filtration and overall performance of our Tier1 filters!