RIDGID HEPA Material Pleated Paper Wet/Dry Vac Replacement Cartridge Filter for Most 3 to 4.5 Gal RIDGID Shop Vacuums (4-Pack) VF3600A - The Home Depot
Vacmaster HEPA Material Fine Dust Cartridge Filter and Retainer (works with Shop-Vac)
WORKPRO 4 Gallon Wet/Dry Vacuum, 4 Peak HP Shop Vac Cleaner with HEPA Filter, Hose and Accessories for Home/Jobsite - Walmart.com