Additional Foam Pre-Filter: DCV501HB filters have the foam ring gasket with excellent sealing, without dust leakage. Using with a foam pre-filter can keep big stuff from clogging filter. : DCV5011H HEPA filter compatible with for DCV501HB 20v cordless handheld vacuum.(Please check your model carefully) HEPA Filtration: DCV5011H filter is made of pleated filter paper, traps 99.97% of dust as small as 0.3 Micrometres; folding filter paper provides a larger area to improve airflow. Easy Cleaning & Washable: Filter material can be washed and reused for better filtering of debris. Rinse with water and letting it air dry completely before reinstalling it for use.