The RIDGID VF3700 (54218) Wet Application Foam Filter for 3 to 4 1/2 Gallon Wet/Dry Vacuums is designed for higher volume liquid pick-up. This wet filter adds protection for your vacuum during wet pick-up by keeping water-borne debris out of the motor. This filter is also reusable and can be cleaned easily with water. The filter fits all RIDGID wet dry vacs 3 to 4.5 gallons. With its patented QwikLock feature, the filter simply snaps on or off the vacuum for easy cleaning.