Looks like Kersten pedestrian WeedBrush . Can be hired for about £300 for the weekend. Great sweeper but does it clean the paving??
Similar product discussed here.
Good luck dealing with Kersten, we had a Vela vacuum complete nightmare from memory cost around £4K , when it worked it was great but it spent more time at their workshop then working, over engineered German *****, agreed to buy it back off us after it spent 8 wks in their workshop awaiting replacement bearing for the 3rd time!
Kersten also sell snow sweepers, so if you have a 'standard' sweeper with an issue at winter time forget it as they prioritise the seasonal sweepers.
The Vela removed moss via the gulley brush but it wont remove algae.