Carbon filter is a replaceable element of the Odour and VOC HEPA drum filter, indicator light glows red on your air purifier when the filter needs to be replaced, best for odours and VOCs, Compatible with the Z-3000 & Z-3500 air purifiers. This carbon filter is a replaceable element of the odour and VOC HEPA drum filter with 3 layers of activated carbon pellets offering an unprecedented level of defence against unwanted odours in your home. Specifically designed to help combat common cooking and cleaning odours, and reduce airborne VOCs such as ammonia, acetone, formaldehyde in the air and around the room. To keep your air purifier performing at its best, it's recommended to replace the odour and VOC carbon filter every 3 - 4 months (depending on usage) . Best for odours and VOCs Pack includes: 1 x Carbon filter Compatible with the Leitz TruSens Z-3000 & Z-3500 air purifiers.