Thank you for contacting RIDGID.
WD09450 is not designed to accept filters bags. However, we have four filters available to fit the wet/dry vac.
The VF4000 is for general purpose dirt, the VF5000 is for fine dust like drywall dust or sawdust, and the VF6000 is designed for very fine filtration such as allergens, pet dander, and mold spores and VF7000 for liquid pickups. You can buy the filters at your local Home Depot store or you can order through our Customer Service organization over the phone 1-800-4-RIDGID (1-800-474-3443) or on-line at www.ridgidparts.com using this link http://ridgidparts.com/accessories/vacfilters.phtml
If you have any further questions or concerns, feel free to contact us at 1-800-4-RIDGID (1-800-474-3443) or you may send your email to firstname.lastname@example.org.