Purina Tidy Cats Lightweight Instant Action Multiple Cats Clumping Dust Free Litters Fast, Strong Odor Control. TidyLock Protection Locks Away Ammonia, Urine and Fecal Odors. Light, Tight Clumps for Easy Scooping. 99.9% Dust Free. 8.5 lbs Tidy Cats LightWeight = 20 lbs Leading Clumping.