The OnGuard 3” Maxi-Clor Super Chlorinating Tablets were designed to disinfect pool water, eliminate mineral scale buildup, and clean your swimming pool water in a manageable size. Created to maintain a clear pool of all sizes, these chlorine tabs also have superior sun protection and a slow-release formula to slowly distribute chlorine to your pool over the course of days. Keep your family and friends entertained by the pool all summer long by keeping a supply of OnGuard pool chlorine handy. The convenient 5 bucket contains convenient 3 inch chlorine tablets. OnGuard is a trusted name in pool and spa maintenance products. These super chlorinating tabs were designed to be easy and effective in sanitizing, chlorinating, and producing clean and clear pool water. OnGuard Chlorine tablets work well with vinyl-lined pools and salt systems. Apply the recommended number of tablets to feeders, floaters, or skimmer baskets using the instructions on the rear of the bottle as a guide. Active Ingredient: Trichloro-s-triazinetrione (99%).