Roebic LB Foaming Root Killer, a powerful solution for clearing roots in pipes up to fifty feet in a four-inch diameter pipeline. This flush application in toilet effectively kills existing roots and helps prevent new root growth. It leaves a temporary coating on the pipe to temporarily block new growth, ensuring long-lasting results. Safe for surrounding trees, ground cover, and natural bacteria in septic systems, this copper sulfate-free formula is used annually for optimal performance. Put your mind at ease about your sewer pipes with ROEBIC Laboratories, Inc 1 pounds. Foaming Root Killer.