The Purina Tidy Cats Clumping Cat Litter is a powerful and effective way to keep your cat’s litter box clean and fresh. The one-pound box includes a 38-pound bag of litter that has been treated with a powerful ammonia blocker to prevent odor for up to two weeks. The multi-layer design absorbs odor quickly and effectively, while the clumping action makes it easy to scoop out debris.