Thank you Guy 
I’m sorry indeed but I couldn’t tell anything about quality.
But I’m pretty sure that these belts are very similar to that orange type of the Strida S30X - which is sold for an exorbitant price!
https://www.ww.stridanederland.nl/en/shop/orange-strida-belt-for-strida-5-lt-sx-and-evo/
Note that this is NOT a Kevlar belt!
I told Friso already on 16th August 2019 and he replied:
“Throwing pearls in front of pigs…”