Recommended are Bando (OEM) or Mitsuboshi belts. Japan Quality and long lasting.
Parts Number:
Mitsuboshi MI069
available from several online dealers in Europe.
Kymco Bando 23100-LCD4-E0A
(same belt as for the Kymco People 200i)
Probably only available via dealers. Or Ebay from China directly.
https://www.ebay.com/itm/ORIGINAL-KYMCO-BELT-for-KYMCO-PEOPLE-S-200-LIKE-200i/181826689786?hash=item2a55b71afa:g:MvAAAOSwBahVRfdmBut you can of course also use other brand belts with the proper specs (Malossi, Dayco, Gates etc.).
But in any case also be aware of the correct turning direction on installation (arrows).
As a guideline here are the "approximate" specs I found out so far (each belt differs a bit from manufacturer to manufacturer):
795mm to 799mm in lenght (outside circumference).
19.8mm to 20.5mm widht.
30° Angle
Be prepared for slightly different performance behaviour on each different belt.
These belts with slightly different lenghts and different widhts have direct influence on the gear ratio and top speed.
And try to find a relatively "fresh" one. Check - if possible - the manufacturing date of the belt. You wouldn´t want to buy a 10 year old belt as brand new. Would you?
Good luck!