Maximum Horticulture 6 inch inline duct booster fan for indoor growing Maximum Horticulture inline booster fan helps move air through your ventilation system Designed for 6 inch ducting, flexible or rigid; 1 end with a crimp and bead design for an easy installation Sleeve bearings allow for installation at almost any angle Energy efficient fan moves free air at 160 CFM and max boosted at 250 CFM Plastic blades provide efficient whisper quiet operation