Review on 🌀 AC Infinity MULTIFAN S7-P Dual 120mm AC-Powered Fan with Speed Control – Ultra-Quiet, UL-Certified for Receiver, DVR, Playstation, Xbox & Component Cooling by Robert Castro

I have two pairs, one to cool my home theater (USB powered on one of my TIVOs) and another set I used to provide air movement around my two cat litter box to add. Yes, seriously, it totally worked. At the lowest settings they still move quite a bit of air and you can't hear them at all, even from 3 feet away. On medium settings, you can hear them a little from about 10 feet away, but not enough to hear them even in the quietest part of the movie. At higher frequencies, they might still work depending on how you use them (you probably won't hear them in the back of a closed A/V case). Rubber washers dampen vibrations well.