Summary As with my earlier one this one only uses one Fan with plenty of air flow. I used this one http://www.amazon.com/gp/product/B00EL938E6?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00 Five of them for around $11.00 and it's a 5 volt fan but you can run it at 12 volts with no problems. This way you get a good bit of air flow. I have been using this for a little over 7 mounts now and had no problems. I do recommend using a variable voltage regulator so that you can set it to your need on the spot. I used this LM317T http://www.amazon.com/gp/product/B00AUECKR2?keywords=lm317t%20voltage%20regulator&qid=1447775526&ref_=sr_1_2&sr=8-2 from Amazon you get ten for around $6.00. and it is very easy to build it. Created with Design Spark Mechanical. http://www.rs-online.com/designspark/electronics/eng/page/mechanical Have a great day! :-) Robert KB3LNN