K-77 clears existing roots from pipes. Roots are destroyed at the point of entry into pipes. Re-growth is prevented because unlike root cutting machines, K-77 chemically kills roots. Once killed, the dead root "seals off" the point of entry and the root cannot re-grow. Non-corrosive and safe for all types of plumbing. Will work without harming surrounding trees, ground cover or the natural bacteria content in septic tanks and cesspools. Destroys clogging roots fast. Saves costly digging and rooter service. Safe for all plumbing. Will not harm septic tanks. Easy to use.