Freshens and cleans the urinal twice as long as most regular blocks-up to 2400 flushes. Protects drains; pliable screen traps more debris for extra drain protection. Source reduction-no cello bag throw away; block is wrapped in water-soluble film. Reduces splash back. Patented "non splash" design keeps liquids where they belong. Biodegradable formula. Low voe (per CARS and OTC). 12 per box