CLR PRO Automotive Heavy Duty Radiator Flush and Cleaner Heavy duty radiator flush and cleaner designed to remove heavy scale build up and rust to help extend the life of your vehicleWith an average 3 gallon radiator, CLR PRO Heavy Duty Radiator Flush and Cleaner is perfect for car maintenance kitsContains no ammonia, alcohol and phosphates Extends the life of your vehicle by removing heaving scale build up and rust. Part of the EPA's Safer Choice Program recognizing the products as a safer alternative to traditional chemicals. We are thrilled to be a part of an organization that is so supportive of diversity in the marketplace. CLR products are made right here in the United States, helping to support U.S. jobs, and enables greater control over supply and quality.