MERV 8 Efficiency Rating - > 90% Dust Arrestance Efficiency per ASHRAE 52.2 100% Synthetic Media - Excellent Dust Holding Capacity - Durable Enough to Withstand Tough Applications - Low Initial Resistance - Saves Energy Heavy Duty Beverage Board Frame with Water Repellent Adhesive - Moisture Resistant - Pleats Hold Together Even When Wet - No Delaminating, No Excessive Buckling, No Collapsing - Stands Up to Rough Handling & Difficult Service Conditions Two-Piece Frame Construction - Provides Added Strength & Rigidity - Will Not Rack, Warp or Bend Under Most Operating Conditions Galvanized Steel Support - Rust Resistant - Maintains Pleat Shape and Prevents Fluttering - Improves Dirt Loading Characteristics Throughout Life of Filter