The Dogness Travel Bowl Duo Filter pack includes 6 replacement filters for your convenience. Each filter uses one-way filtration technology with activated carbon to effectively block small impurities and keep the water in your Travel Bowl Duo clean and healthy. With this filter pack, you can maintain the filtration system of your Travel Bowl Duo and ensure your pet has access to fresh water wherever you go. Key Features: - One way filtration - Activated carbon - 6 pack