Karcher 9.556-010.0 RM 110 Pump and Coil Protectant Concentrate (5-gal. but can make up to 55gal)Pump and Coil Protectant Concentrate is a multi component product made from heat resistant organic and inorganic salts. Its stabilizing action on the minerals, which causes hardness in water, is based on its ability to impede the growth of mineral deposits. This product is proprietary to machines that have a built in dispenser for this product. Keeps your machine running efficiently with optimum performance and reliability.