Moflo is the best instant drain unblocker on the market. Sulfuric acid-based drain opener. Designed to quickly dissolve all organic obstructions such as cloth, paper, rags, grease, hair, paper, sanitary napkins, styrofoam, sludge, soap, and coffee grounds. Use in floor drains, sink drains, tub drains, shower drains, and other drains prone to clogging. Moflo has an instrument for approval for use in food processing establishments for use as a drain cleaner. Removes lime scale and rust deposits from drains and traps Safe for use in metal or PVC plumbing systems Formulated with virgin-grade 99% sulfuric acid Inhibited to prevent flash rusting Will not harm septic tank activity