MH 4" Carbon Filter Only Grow Tent Odor Control Hydroponic Ventilation Designed for hydroponic grow tents, indoor gardening, and ventilation systems. Helps eliminate odors, dust, and airborne particles when used with a compatible inline duct fan. Features Brand: MH Type: Carbon Air Filter Flange Size: 4 Inch Color: Black Material: Steel Housing with Activated Carbon Compatible with 4" Inline Duct Fans Ideal for Grow Tents, Hydroponics, Greenhouses, and Ventilation Systems Reversible Design for Extended Filter LifeOnly parts in the picture is included. Package Includes 1 × MH 4" Carbon Filter As pictured