MERV 11 Efficiency Rating - > 95% Dust Arrestance Efficiency per ASHRAE 52.2 - Exceeds Specifications for Hospital Filter Efficiencies 100% Synthetic Needled Fiber Media / 14 Pleats per Foot / Electrostatically Supercharged - Electrostatically Charged Fibers Attract Fine Particulate Like Dust on a TV Screen - Improved Depth Loading for Excellent Dust Holding Capacity - Lower Resistance than Most High Efficiency Filters - Durable Enough to Withstand Tough Applications 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