5-20 Gallon, Hepa Cartridge Filter & Retainer, For Vacuuming Household Debris, Fine Dusts & Filtering Allergens, Mold Spores & Pollen, Captures Particles Down To 0.3 Micron In Size, Fits Vacmaster Wet/Dry Vacs 5 Gallon To 20 Gallon, Fits Most Shop Vac Wet/Dry Vacuum Cleaners 5 Gallon & Larger.