Razor 4-Pin Electrical Kit for the following models: MX350 Dirt Rocket, Versions 33 and up MX400 Dirt Rocket, Versions 33 and up Note: Model versions can be determined based on your 8-digit product ID code. The product ID code can be found on the battery cover and/or on the bottom of the frame. The last two digits are the version number (e.g. "01"=version 1, "02"=version 2, etc.)