Hagen Catit Magic Blue Cartridge fits to all cats’ litter boxes, this includes reusable plastic holder and 2 filter pads', "This Hagen Catit Magic Blue Cartridge absorbs and retains up to 80% of ammonia and reduces fecal odors by an average of 40%, depending on your cat's cat food diet", 'Safe and easy to use in any cat litter pan, the pads are also non-toxic and unscented, Catit Magic Blue Cartridge also absorbs hazardous ammonia gases found in cat litter 25 times more effectively than carbon-based filters, This cartridge is easy to disassemble and clean and it’s made of BPA-free materials that’s safe for your cats Box Contents:1 x Hagen Catit Magic Blue Cartridge for Cat Litter Box