Arm & Hammer Double Duty Cat Litter Deodorizer. Keep your litter box consistently fresh with Arm & Hammer Double Duty Cat Litter Deodorizer, the #1 Cat Litter Deodorizer Brand featuring an extra-strength formula in a generous 30 oz (850 g) package. This powerful deodorizer is formulated with Arm & Hammer Baking Soda Crystals to eliminate both feces AND urine odors on contact, proven in lab tests to maintain lower odor levels for 9 days compared to litter alone. Safe for daily use around both cats and owners, this product works effectively with any type of litter (clay, scoopable, or natural) and features a moisture-activated scent that refreshes every time your cat uses the box. Instructions: Sprinkle a layer on the bottom of a clean box, add litter, mix in more deodorizer on top, and repeat daily between litter changes for ongoing freshness.