You will need to determine the version number of the scooter in order to purchase the correct rear wheel assembly. If you just need a tire or tube, or a sprocket, freewheel, or brake then the version number of the scooter is not needed though.
The Razor E300 electric scooter's version number is located on an ID tag which is located on the scooter's original battery charger, handlebar stem, and underside of frame. It is also on the scooters original cardboard box if you still have it. The ID tag looks like this:
The 7th and 8th numbers on the Razor® ID tag are the version number. For example:
Here is a chart showing where the ID tag is located on all Razor electric powered vehicles.
Hopefully this will help. Please let us know if you have any questions.