For use with HD Electric Aerators only. For Windmills and EL2 Electric Aerators use the standard Freeze Kit instead.If you are in a colder climate then we recommend attaching the Koenders HD Freeze Control Unit. When you compress air condensation can form in the airline and can create an ice blockage if temperatures dip below freezing. With a Freeze Control Kit alcohol will be automatically injected to melt the blockage. This will help ensure aeration during winter as well as protect the compressor from additional wear and tear due to backpressure. We recommend using Isopropyl Alcohol at 90-99% purity. (1-1-1413)