The So Phresh Petco Brand Odor-Lock Crystal Cat Litter is designed to help reduce litter tracking in your home. This cat litter features an odor-lock formula that helps prevent unwanted odors from escaping, and it can even be used to lock in odors for up to a month. The crystal cat litter is also lighter and less dusty than other clay litter varieties, making it ideal for use in high-traffic areas.