Whisker carbon filters eliminate unwanted litter box odors. Designed for use with the OdorTrap system, these activated-carbon air filters trap and neutralize smells, ensuring a fresher environment. They are compatible with Litter-Robot 4, Litter-Robot 5, and Litter-Robot EVO. For optimal odor control, replace the carbon filter monthly. These flexible pads sit directly over the waste drawer, actively working to absorb any lingering odors.