The Kärcher KFI 3310 Cartridge Filter allows you to vacuum without any need for additional filter changes. The filter can be easily attached and removed by twisting it. No additional locking elements are required. In addition, the filter ensures excellent dust retention. Suitable for the Karcher WD 1 Compact Battery, WD 2, WD 3, WD 3 P and the SE 4001 Wet Dry Vacuum Cleaners.