Question about Kärcher Brush Rollers

Michael A688 has described it to the punt.

They are harder than those for wood and remove green deposits well on smooth stone slabs. On uneven, i.e. mottled slabs or those with rough surfaces, something will stick in the recesses. A high-pressure cleaner is better suited for this.

Sorry,
On other pages I find the brush for wooden floors at Fr. 29.90
and a different quality for stone floors at Fr.34.70
What is correct?

Works quite well on stone (garden slabs)