
The AirSupply 4 Inch Duct Fan helps with all of your ventilation issues. The ES4 inline fan increases the centrifugal airflow vortex of your ventilation system to remove heat and humidity from grow tents, electronic equipment closets, and industrial workspaces. The airflow direction is reversible and can be used to intake fresh air into space or exhaust hot air or fumes from your space. It can even be used to pull air through odor-reducing carbon filters in grow tents.
Compared to old-school AC or DC motors, our brushless DC (also known as EC motor) and variable speed controller lets you precisely control your fan speed from 0-100% to increase efficiency while reducing noise and power consumption. With easy installation and reduced maintenance from the pre-lubricated bearings, the TURBRO AirSupply ES4 Inline Duct Fan will provide constant airflow for years to come.
Features:
√ Energy Efficient - Consumes up to 60% less power
√ Compact Design - Yet Powerful Ventilation with 195 CFM air flow at 5,000 RPM
√ Brushless DC Motor - Quiet Operation, Lasts 3x longer than AC motors
√ Variable Speed Controller - 0 to 100% speed control in 1% increments
√ Multiple Mounting Options - Hardware kit included for wall mounting
Package Includes:
1× 4'' Duct Fan (with a 6 ft. power cable and 3-prong plug)
1× Speed Controller (with 16-ft cable)
1× Installation Kit (Includes screws and anchors)
Specifications:
- Model: ES4
- Duct Size: 4 Inches
- Air Flow: 195 CFM
- Rated Speed: 5,000 RPM
- Maximum Pressure: 335 Pa
- Noise Level: ≤ 37 dB
- Speed Controller: Potentiometer 0-100%
- Environment Requirements: 15-140 °F, 15-93% RH
- Water Proof: IP44
- Certification: ETL Listed
- Power Supply: 120V, 60Hz
- Rated Power: 18 W
- Current: 0.16 A
- External Material: Aluminum Alloy
- Weight: 2.7 lbs
- Dimension: 6.26 x 7.24 x 5.91 in

I believe it really produces 200 CFM
I bought the popular black, plastic $25 dollar one that claims to have almost 200 CFM, and this one from AirSupply seems at least twice as strong when it is on max. Note: the black, grow tent 4" hose reduces the noise on it a great deal.

its a well built rig
when i bought it it had no reviews so i took a chance. It works very well. Its all metal, the ends unscrew so you can clean the fan when needed. The lil Pot switch works pretty well. I used mine to remove excess humidity and heat from my laundry room. it get a lil loud when it is on high but the washer and dryer outweigh it in noise.It has very good suction. I high recommend the product. its high quality all around. Now it does depend on what you use it for. Mine is connected to a 4 foot ridgid dryer vent too the outside. Other that that its wide open. Only thing left is the longivity. So far so good.