Enzymatic deodorant block contains surfactants and chelating agents to clean and deodorize for 30 days (up to 2,000 flushes). Bluing agents are released with each flush so you know that it's working. Increased ventilation reduces potential splash back and flexible screen traps more debris to prevent costly drain clogs. Block packed in environmentally safe PVA water-soluble film. Built-in disposable removal tool helps to prevent cross-contamination.