Keeps lines free from clogging tree and shrub roots. Roots have the ability to seek out small openings in pipe lines in search of water. Once a pipe is penetrated, rapid growth in the pipe causes blockage. This formula is proven by years of success in clearing sewer and drains of root growth, etc. Fast and easy to use. Harmless to bacteria in septic tank and cesspools. Prevents root blockage for a full year.