Litter Pearls Ultra Clump cat litter with ODORBOND is the ultimate clumping litter for odor control. Litter Pearls was the first U.S. brand of crystal cat litter and is made with the highest quality Silica Gel crystals available. Silica Gel is safe, non-toxic and allergen-free. Not only are Litter Pearls crystals safe for cats and people, they are also lightweight with the highest absorbency properties, requiring less litter than clay and other types of litters. This means, using Litter Pearls, less litter per cat ends up in the landfill. Ultra Clump's powerful odor control captures ammonia odors on contact. When used as directed, Ultra Clump will control ammonia odors for up to 30 days, keeping the litter box fresher, longer. Litter Pearls Ultra Clump Crystals are super soft on paws for a pleasant litter experience.