The PetSafe® Litter Box Replacement Carbon Filters help eliminate odors in your PetSafe® Simply Clean® Automatic Litter Box. Simply slide the filter in the slots under the litter box conveyor cover. The dual-action carbon pad traps odors to keep your kitty’s litter box smelling fresh. One filter can last up to 4 weeks. PetSafe® brand is here to help you and your pet live happy together™. Compatible Litter Box – The filters are compatible with the newest, gray version of the PetSafe® Simply Clean® Automatic Litter Box Easy-to-Fit – Simply slide the filter into the slots inside the cover and replace over the waste area Reduced Odor – Dual-action carbon pad traps odors to keep your cat’s litter box smelling fresh Long-Lasting Filter – Each filter can last up to 4 weeks