2-Ply Poly Ring Panel, Filter Efficiency 0.25, Height 12 In., Width 12 In., Thickness 1 In., Frame Type Sturdy Internal Wire is Heat Sealed Inside the Polyester Layers Creating a Self-Gasketing Filter, Initial Resistance 0.28 In. WC, Final Resistance 1 In. WC, Max. Temp. 150 Degrees F. Only shipped in quantities of 24.