1. Perfect Fit for Shark Models: Designed specifically to work with Shark BU3523 BU3521 BU3520 vacuum cleaner equipment. These filters maintain optimal performance and extend the life of your vacuum cleaner. 2. Washable and Reusable: Wash these filters with clean water, let them dry completely, and reuse them to save money. For optimal performance, it is recommended to replace the filter set every 2-3 months to maintain the efficiency of your vacuum cleaner. 3. Easy Installation: No tools are required to replace these filters. Maintenance is easy and simple by simply removing the old filter from the vacuum cleaner and replacing it with a new one when necessary. 4. Versatile Cleaning Capabilities: Designed to handle everyday messes, this filter excels at capturing dirt in a variety of scenarios, such as sawdust, wood chips, and hair, making it a must-have tool for your home environment. 5. Enhanced Durability for Long-Term Use: This replacement filter is built to withstand regular use and maintain its functionality, helping you keep your space clean without frequent replacements. Function: Consumables Use environment: Home use Colour:As Shown Material:plastic Package Contents: 1 * filter screen 1 * filter element 2 set * 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.