This Catit Magic Blue air purifier is 25 times more effective than an activated carbon filter & is free from all chemicals, as well as being easy to use. It offers enhanced air quality in enclosed litter trays as well as in the surrounding environment & is entirely natural. The small filter pads are in cartridges that your cat cannot access & can be easily attached to the top of the litter tray. The pads absorb the unpleasant odours like a sponge, rather than merely trying to mask the smell as chemical air fresheners do. This purifier can help remove up to 80% of ammonia gas, which is particularly pungent & can cause adverse reactions in cats, other pets & children. Stool odour is also reduced by an average of 40%, depending on your cat’s eating habits. Catit Magic Blue is the ideal alternative to toxic chemical air cleaners. It fits in every litter try & keeps your home fresh & hygienic! Catit Magic Blue at a glance: Air purifier for enclosed litter trays Efficient & natural: free from chemicals & completely non-toxic, as well as 25 times more effective than activated carbon filters High absorption rate: absorbs unpleasant odours rather than merely masking them Up to 80% less ammonia gas: particularly effective against unwanted ammonia gas, which can be harmful to the health of pets & small children Absorbs approx. 40% of stool & urine odour: significantly fewer excrement smells, depending on your cat’s diet Easy-to-use: replaceable filter pads in cartridges are slotted into the docking station which is attached to the top of the litter box interior Fits every litter tray: handy format Clever alternative to toxic or chemical air purifiers Please note: The Starterset (variant number 583578.0) comes in the blue packaging & contains the air purifier & 2 Catit Magic Blue filter pads, which provide fresh air for up to 1 month. The Refill Pack (variant number 583578.1) comes in the green packaging & contains 6 Catit Magic Blue filter pads, which will provide fresh air for up to 3 months.