I'm specifically talking about the model Okai ES400A here. It looks like this:
.I bought it for a cheap price as a defected vehicle. It obviously misses a few parts.
It was not possible for me so far to ride it and I only found 2 pages with possibly working conversion kits for it which are batteryprovider (http://www.batteryprovider.com/products ... ES200.html) and scooter-unlock (https://scooter-unlock.eu/shop/). However none of these shops declares their conversion kit as suitable for the ES400.
Thanks for information.