Zep Drain Defense Liquid Build-Up Remover 64 oz, Pack of 4Slow drains can be frustrating and inconvenient for household routines. Drain Defense Pipe Build Up Remover is formulated with specialized enzymes that remove years of buildup to clean your pipes of grime and debris. Use monthly to prevent backups and bring your house back to normal operations. Safe for all pipes and septic systems Provides 21 months of drain protection Use monthly to prevent clogs, slow drains and restore flow For use in sinks,