With this version of the Kärcher WD 3 S V-17/4/20, you get 4 extra vacuum cleaner bags. You have a supply right away and won't be without vacuum cleaner bags this way. The WD 3 S V-17/4/20 has a stainless steel casing, which is different from the original WD 3. The advantage is that the vacuum can withstand water damage better and lasts longer. The machine has a 17L dust and liquid reservoir, so you can also vacuum wet dirt. That's useful, because you can do the most diverse jobs in and around the house. You can rinse the filter of the construction vacuum underneath the faucet. A clean filter ensures the best suction power.