TruSens - Replacement Activated Carbon Filter for Pet Filter Drums. This filter, featuring 2 layers of activated carbon pellets, provides a protective barrier against unwanted pet odors in your home. This activated carbon layer is specifically designed to remove odors and volatile organic compounds (VOCs) and is compatible with the Pet HEPA filter drum. To maintain the optimal performance of your air purifier, it is recommended to replace the Pet activated carbon filter every 3 months (depending on usage). This activated carbon filter is a replacement part for the Pet HEPA filter drum. The replacement indicator on your air purifier will light up red when the filter needs to be changed. For the best cleaning results, it is recommended to replace the Pet activated carbon filter every 3 months (depending on usage). Ideal for combating pet dander and odors. Package includes: 1 x activated carbon filter.