Best on toughest clogs. Safe for all pipes. Don't get caught without it. Patented gel penetrates and dissolves clogs. Works fast to clear fully clogged drains with standing water and slow drains. Removes hair, gunk, grease and soap scum. Safe for all pipes like PVC, plastic, copper, old pipes, septic systems and garbage disposals like for garbage disposals, follow same usage direction and flush with disposal running. Contains no phosphorus.