The Catit Airsift Pod is a reusable holder designed to perfectly frame the Catit Airsift filter and to work with any covered cat litter. The pod comes with a Catit Airsift filter and strong adhesive tape for installation into the cat litter. The Catit Airsift filter helps reduce unpleasant odors from the cat litter by combining two cat-safe filter media: Catit Magic Blue Ammonia Buster and activated charcoal for enhanced efficiency. A Catit Airsift filter lasts for 30 days (based on a household with one to two cats and daily litter cleaning). Refills are sold separately.