Another voucher for the Yeah Racing 30mm aluminum fan. I've heard some people complain of the noise and wear them out on high voltage by soldering the wires directly to the battery posts, but in my experience using 7.4v bec, they last a very long time and move a good amount of air. Just make sure to secure the wires leaving the fan case as they can easily come unsoldered, a small dab of shoe goe will prevent the wires from pulling off and you'll have yourself a very dependable fan.