Still air incubators are a great low cost form of incubation for eggs, however, experienced hatchers know the best way to improve hatch rates is to have a constant flow of warm air circulating around throughout the incubator. With that in mind Farm Innovators incubator Digital forced air fan kit is specifically designed as an add on fan for the model 2150 or as a replacement fan for the Pro Series 4250 incubator. The fan comes completely assembled with easy to follow mounting instructions and quick connect wiring. 110 volt