Carbon filter is a replaceable element of the Pet HEPA drum filter, indicator light glows red on your air purifier when the filter needs to be replaced, compatible with the Pet HEPA filter drum for all Leitz TruSens Z-2000 & Z-2500 air purifiers. This carbon filter is a replacement element of the pet HEPA drum filter with 2-layers of activated carbon pellets offering a level of defence against unwanted pet odours that can invade your home. Specifically designed to remove pet odours and VOCs, this carbon layer is compatible with the pet HEPA filter drum for all Leitz TruSens Z-2000 & Z-2500 air purifiers. To keep your air purifier performing at its best, it's recommended to replace the Pet carbon filter every 3 - 4 months (depending on usage) . Best for pet dander and odours Pack includes: 1 x Carbon filter Compatible with the Leitz TruSens Z-2000 & Z-2500 air purifiers.