Ideal for winterizing recreational water systems. Provides corrosion protection. Burst protection to -50 degrees F. RVs, boats, swimming pools, vacation homes. Ready to use. The product will freeze at approximately 5 degrees F , this is not harmful to your water system. Ideal for use in: boats, swimming pools, rvs, mobile homes, vacation homes. Safe for use in all types of potable water & plumbing systems. Safe on copper, brass & plastics (except acetate).