Features: It is portable and easy to use. The cartridge filter is to keep your water clean and fresh. Prevents dirt from entering the pump and heater and prolongs service life. For maximum efficiency, clean cartridges each week and replace once a month or sooner. The filter cartridge is installed inside the filter pump and captures dirt as it passes through the system.Specifications:Material: PPHeight: 74mmInner diameter: 43mmOuter diameter: 108mmCompatible with: for PureSpa S1 TypePackage included:1 x Filter CartridgeNotes:1. Manual measuring, please allow 1 ~ 3mm error,thank you.2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. We guarantee the style is the same as shown in the picture.