TyDBol Automatic Rust Tablets provide a clean you can see by eliminating rust stains in your toilet. This automatic toilet cleaner does the work for you, all you have to do is flush. These tablets not only eliminate rust, but also repel rust for up to 4 weeks (per tablet). TyDBol Rust Tablets won’t harm your toilets and are safe for septic systems. Not only do these Rust Tablets fight rust stains, but they also help eliminate hard waters stains. While the tablets go in the tank of the toilet, they keep your entire toilet system rust free with every flush. Don't let rust stains become a problem in your bathroom - Use TyDBol Automatic Rust Tablets for easy cleaning that works! Automatic toilet cleaning tablets. Automatically removes rust stains with every flush. Safe for plumbing and septic systems. Each tablet lasts up to 4 weeks. Eliminates rust and hardwater stains.