The rollers are there to clean and are effective and machine washable without losing their quality ... and their materials are not too defined but I say a mixture of cotton microfiber ...

Answer Microfibre

Further dirty water tank too small

Dirty water pipe

And much more

Ongoing trouble

The nonwovens of the yellow castors for hard floors (not stone) are made of synthetic materials.
https://www.perplexity.ai/search...

Depending on the nature of the floor, it should be noted that there are different castors.

The appliance is definitely highly recommended for household applications. I've been using it for over 2 years and can only say it's great!
https://www.stern.de/digital...

Hello, the rollers are made of cotton with a microfibre blend, and clean up is perfect.