Yescom 4" Inline Duct Exhaust Fan 4inches Hydroponics Cooling Vent HO 2580RPM Air Ventilation Blower UL listed, CCC, CE, RoHS Certificated for safe use Powerful and high efficiency - 2580 RPM and 175 CFM. Overall Dimension:11-1/2"L x 11-1/2"W x 8"H Flange: 4" Dia Moisture resistant - great for use in damp environment