Apollo Horticulture 6&rdquo; Inch Premium Carbon Charcoal Air Filter Scrubber 1 - 6 Apollo Horticulture Premium Carbon Air Filter Air Flow  450 CFM / Dimensions: 9.75" x 21.50" with 6 Flange Ducting RC 48 Virgin Activated Carbon / Aluminum Cap Construction for Maximum Output 50mm Carbon Layer of Thickness for Higher Absorption and Performance Package Includes: 1  4 Carbon Filter / 1  Pre Filter