Easyfilter ball bags (SET OF 4 BAGS) allow you to replace the cartridge in Waterair CW100, CFR100, Sherlock filtersWith 5 micron filtration for a crystal clear waterECO RESPONSIBLE bags of balls can be washed in the washing machineCleaning every 2 to weeks is enoughCheaper than cartridgeThe size is manually measured, please allow the error (1-3cm).Due to different monitor pixels, there may be color difference, please refer to the actual product.After receiving the package, if there is any dissatisfaction, please contact me first, do not leave negative feedback easily, thank you and have a nice day.Note: The data is all measured manually, please allow 1-3cm error, due to the light and display difference, there are will have a certain color difference, the actual object received shall prevail.