Simple and convenient: the cartridge filter allows you to vacuum without additional filter changes. This filter can be easily attached and removed by turning it. No additional locking elements are required. In addition, the filter ensures excellent dust pick-up. Suitable for the Kärcher wet and dry vacuum cleaners WD 1 Compact Battery, WD 2, WD 2 Plus, WD 2-18, WD 3-18, WD 3 (Battery), and the Kärcher spray-extraction cleaners SE4, SE 4001 and SE 4002.