Keep your toilet looking and smelling clean between regular cleanings with Soft Scrub DuoCubes. These easy-to-use, in-tank cubes continuously clean and freshen your toilet with every flush. Just drop a cube into your toilet tank and let it do its work. Safe for toilets and septic systems, Soft Scrub Duo Cubes help fight stains and deliver a clean, fresh scent. Now, with added Anti-Clogging Technology that helps dissolve toilet paper residue over time.* Each cube lasts for up to 4 weeks. *Formulated to help dissolve toilet paper residue over time. Not a clog remover.