Longer lasting clean: The body uses premium blue filter paper, which makes it easier to keep the water clean than common filter paper. Enjoy clean bathing and fun with your family and friends. Compatible model: The replacement cartridge filters are compatible with all RELXTIME spa pools. Outer diameter 100mm (9.9cm), inner diameter 60mm (6.1cm), height 79mm (7.9cm). And are conveniently sold in 6 packs. The spa filters are the best partner for your hot tubs. Maintain and reuse: It is recommended to change the spa filter regularly to maintain filtration efficiency and replace it every 2-3 days during heavy usage. To ensure a constant replacement pool filter performance, clean your spa filter cartridge replacement before and after use. The filter can be used repeatedly after proper cleaning and maintenance. Powerful filtration performance: The pool cartridge filter features extra-durable plastic and quality dacron fibre pleats, even the finest dirt particles can collect, such as hair, leaves, dust, sediment, and sand, and ensures clear and clean water. Easy to clean and replace: This practical blue filter can be cleaned very easily, simply remove the filter from the water inlet inside the spa, remove the cartridge, you can scrub the filter with a cartridge cleaner tool, and then wash it under a strong water pressure to remove loose particles from the filter's fabric.