VEVOR Inline Duct Fan, 4-Inch 200 CFM with Variable Speed Controller, Quiet AC-motor Ventilation Exhaust Fan for Cooling Booster, Grow Tents, HydroponicsHigh-efficiency AC motorQuiet an OperationRandomly Control the SpeedIdeal for Indoor UsesComplete AccessoriesDurable for Years to ComeAirflow: 200 CFM,Noise Level: ≤ 50 dB (About 29 dB),Item Size (L x W x H): 12 x 9.3 x 7.5 in / 304 x 235 x 190 mm,Motor Type: Copper Motor,Model: VV-GDFJ-AC4,Air Pressure: 165 Pa,Rated Power: 31 W,Fan Speed: 2550 RPM,Item Weight: 4.4 lbs / 1.98 kg,Voltage / Frequency: AC 110V-240V, 50/60Hz