Amazon.com: PUREBURG VF4000 Replacement Vac Filter Compatible with Ridgid VF4000 72947 Wet/Dry 5 to 20 Gal Also Compatible with Shop Vac Husky 6-9 Gal WD5500 WD0671 RV2400A RV2600B WD06700 WD09450, 1-Pack :
EZ SPARES Replacement for Shop-Vac Craftsman 9-17816 Filter,Wet/Dry Cartridge,for most 5 Gallon & larger Vacs Part Accessories : Tools & Home Improvement - Amazon.com