Lot of 3 Small 3/4" Anchor Patches Nautical Ship Marine Decor Iron-On Appliques Retains the beneficial minerals in water for better health Great value for money with the superior quality Features the same great quality as original filter at a fraction of the price It is recommended to replace the filter every 6 months or 300 gallons, whichever comes first. We are sure you will enjoy the benefits of our product, for concerns, you can contact us and ask refund.