Gallon, Exterior Wood Cleaner, Safe, 100% Bio-Degradable, Won't Kill Plants Or Grass, Concentrated, 1 Gallon Will Make 4 Gallons, Ideal As A Main, Cleaner Or Prep, Revitalizing Old Weathered Wood Prior To Staining, Cleans Dirt/Mold/Mildew, Removes Failed Oxidized Coatings, Fast Acting And Easy To Use, Non-Flammable.