The Catit Airsift Dual Action Odour Reducing Pad is our best-performing filter pad, combining two cat-friendly media: our powerful Magic Blue Ammonia Buster, plus activated carbon to keep nasty smells at bay. Key Features: -Helps to reduce unpleasant litter box odours -Includes Catit Magic Blue Ammonia Buster PLUS activated carbon for higher efficacy -For use in Catit litter boxes with Airsift filter system (Regular, Jumbo, SmartSift) -One filter pad lasts for 30 day Compatible with these Catit litter boxes: 143955, 116246, 123839