KLENZTONE 4 makes cleaning many surfaces easy even the most sensitive types of masonry. Almost as rapidly as you can apply it, KLENZTONE #4 loosens the grime that ordinary cleaners can't touch. Then, after rinising with water, surfaces return to new masonry appearance. Coverage : Approximately 250 - 400 sq. ft. per gallon, depending on the porosity of the surface. Packaging : Gallons 5 gallon pails 55 gallon drums