Product review (4 stars): Does what it says it does
Does the trick.  It's a reliable fan with a hose on it that you put in your draft tower.  It blows cold air into the draft tower, keeping the beer lines cool so you get good pours.  Not much to it.

Small quibble in that the hose often comes disconnected from the fan at the slightest of taps.  So, if you're adjusting the kegs in your kegerator or moving lines or whatever and you tap this thing, the hose will come out and you won't realize it until you do pour a brew and it's half foam.