Rust in the cylinders, caused by moisture, is one of your engine's greatest enemies. Whether storing an engine long term, or just for the winter, you need to install a set of desiccant plugs. The aircraft industry has used these for years. Remove your spark plugs, screw in a set of our special automotive desiccant plugs, and your cylinders are protected. The desiccant changes colour when exposed to moisture, giving a visual indication they are working. Plugs come ready to use, in a dry sealed container.