Designed to penetrate, dissolve and remove odor-causing residue that can occur in all washing machines;Specially formulated tablet dissolves slowly, lasting throughout the entire wash cycle and breaking up residue better than bleach;Safe to use with Front Load Washing Machines and Top Load Washing Machines - High Efficiency (HE) and Conventional Washers;Use once a month to keep your machine fresher and cleaner;Septic tank safe