Clip-on design cleans and freshens with no mess. Antimicrobial protection in the hook to resist odor-causing bacteria. Fights toilet rings and helps to prevent stains. Help maintain a clean, fresh toilet between deep cleans. Clip securely onto rim of toilet, where water flow is maximum. When used up, simply dispose the unit in the trash and replace. Cleans and freshens for up to eight weeks. Application: Automatic Toilet Bowl Cleaner; Applicable Material: Toilets, Urinals; Chemical Compound: Sodium C14-16 Olefin Sulfonate; Sodium Dodecylbenzenesulfonate; Dirt Types: Soils; Odors.