These are the highest quality 99% trichlor 3" chlorine tablets available. Each bucket contains roughly 100 tablets. They are hard pressed 90-percent available chlorine. Perfect for use in erosion-type chlorine tablet feeders or floaters. These tablets dissolve slowly, providing a constant chlorine feed rate. Convenient for use in floaters, and automatic feeders. Stabilized chlorine is U.V. protected against the sun's harmful rays, and these slow-release tablets require less frequent applications. 99% Trichloro-S-Triazinetrione Trichlor is stabilized to protect the chlorine from the ultraviolet rays of the sun.