HTH, 6 OZ, 3", Super Chlorinating Tablets, Sanitizes Pool Water, Stabilized, Sun Protected, For Extended Chlorine Life, For Use In Skimmer Or Floater, Protects Against Bacteria & Algae Growth, Active Ingredients: Trichlors-S-Trazinetrione 93.6%, Zinc Sulfate Monohydrate 3.5%, Other Ingredients 2.9%, Available Chlorine 84%.