Item #: FSB30009 by NORWECO INC is suitable for use in approved, gravity flow chlorinators. Composition: Manufactured from pure calcium hypochlorite, these Bio-Sanitizer disinfecting tablets dissolve slowly and evenly, providing effective and economical bacteria-killing power. Chlorine Content: Each tablet contains a minimum of 70% available chlorine, ensuring maximum effectiveness. Dependable Source of Chlorine: These tablets automatically adjust their chemical application to the rate of flow, making them a reliable, long-term source of chlorine. Packaging Options: Bio-Sanitizer disinfecting tablets come in easy-to-open, resealable containers of 10 lb., 25 lb., 45 lb., and 100 lb., all approved by the Department of Transportation.