I am in the process of building an incubator now and purchased four fans that already had the speed control wired in. Just plug into a 110 outlet and adjust. The only reason I purchased four instead of two is for redundancy. I purchased a herpstat controller and some heat tape. Hope to complete it in the next couple of weeks. I fissure I can build a nice one for about half the price of a new one and customize to my needs.