[Compatible Model]This product is fully compatible with for Clean Cordless Cleaner models including BU3523, BU3521, BU3120. Please confirm that your machine model matches one of our compatible products before purchasing [Washable & Reusable]Maximize cost-efficiency by rinsing our filters thoroughly with clean water, allowing them to dry thoroughly, and reusing them. For performance, we recommend replacing the filter set every 2-3 months to help extend the lifespan of your vacuum cleaner [Easy Replacement & Installation] No tools required for filter replacement. Simply remove and replace the filters from your vacuum cleaner equipment when needed. Quick and convenient, making your cleaning tasks smoother. Please note: the physical slightly color difference or difference, does not affect the use, please do not mind, thank you! Colour:Photo Color Material:plastic Package Contents: 1 x filter 1 x filter element 1set x filter cotton Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.