Keep your spa water clear and clean with a Lay-Z-Spa Type VI Filter Cartridge. This replacement cartridge measures 4.2x3.1 inches and is designed for Bestways line of Lay-Z-Spas. They are lightweight and easy to clean. These cartridges are great for keeping your spa to its highest quality, helps to avoid dirt build-up and prolong your Spas life. Lay-Z-Spa filter cartridges should be changed regularly to keep your filter pump working effectively!