Product review (4 stars): Quality fan, overpriced without a speed controller
Quality fan, but, for the price, should have a PWM speed controller and a longer cord (6+ft).

The fan moves air well, even with back-pressure. My setup delivers air to the top of a three-tap tower via a 3/4" copper pipe (and a 90 degree elbow). Air returns via the empty space in the tower. The faucets cool to ~44F, whereas the kegs are ~38F. This results in a nice pour with minimal foaming.

I purchased an $8 speed controller (https://www.amazon.com/gp/product/B00QIC8UTM) to run an 80% duty cycle (minimizes vibration and should extend the life of the fan).