TekQuest Fresh n Purr Cat Litter Deodorizer Crystals Fresh n Purr Cat Litter Deodorizer Crystals uses an Odor Absorption Technology which reduces unpleasant odors associated with cat litter boxes Safe for cats non toxic and non staining Ultra concentrated, the 2.5-ounce bag lasts for up to 90 days approximately 20 litter box changes Pleasant green apple scent Easy to use