Be sure you are buying from FRESH HEADQUARTERS to get the authentic, made in the USA product. NEUTRALIZE LITTER ODOR at its source with Fresh Headquarters Cat Litter Box Air Filters for domed litter boxes. Activated carbon charcoal pads trap urine and feces odors in their pores so your home smells clean and fresh..6-PACK OF FILTERS provides up to 18 months of cat litter deodorizer, with each lasting up to 3 months. Keep your cat litter box conveniently located without subjecting family and guests to pungent and unpleasant cat box odors..CARBON PAD FILTERS measure 6” x 6.5” and are 1 cm thick. This provides a greater surface area for odor absorption. Pads are trimmable with scissors to accommodate most any brand of hooded cat litter box..NATURAL AND NON-TOXIC cat odor control eliminates litter box smells while giving you peace of mind. Inserted in the vented filter compartment, these pads work discreetly without your feline friend even realizing they are there..EASY TO INSTALL in just seconds, Fresh Headquarters Cat Litter Charcoal Filters are eco-friendly and biodegradable. Toss out the old filter every 2-3 months and replace it with a new one to keep litter box odors at bay.