A Crystal Clear Spas Filter Sleeve improves spa water filtration and is designed to fit most spa cartridge filters. The sleeve may or may not cover your entire spa cartridge filter. Roll the sleeve under at one end if it is too long for your spa filter. Included in the Starter Kit, the Filter Sleeve improves your spa filters effectiveness. Cleaning your spa filter and Filter Sleeve is easy – simply use a garden hose weekly to ensure maximum water purification.