How to change a cartridge filter on a vacuum (Karcher) - YouTube
How to Replace the Cartridge Filter in a Karcher Wet and Dry Vacuum Cleaner - YouTube
Foam Filter For Karcher Nt 48/1 Te, Wd 2.xxx, Wd2.200, Wd2.500 For Wet Vacuuming And Dry Vacuuming Absolute Spare Part - Vacuum Cleaner Parts - AliExpress
Pack of 2 Cartridge Filter Fit Karcher WD2.200 WD3.500 Wet & Dry Vacuum Cleaners | eBay