Cleans and deodorizes with every flush. Colors standing bowl water a fresh aqua as it imparts a nice fragrance. Contains quat, won’t clog drains and is totally water soluble and biodegradable. Contains no acids or paradichlorobenzene. Lasts up to 1,000 flushes (30 days with normal operation). The compound inside gradually dissolves - when it is gone and no longer colors the water, it is time to replace.