Model Compatibility: Fits EX250, EX400, EX500, GPX250, GPX250R, ZZR250, and EX-4 motorcycle models as listed in the title. Functionality: Serves as a voltage regulator rectifier replacement to restore electrical system function for specified motorcycle models. Electrical Specification: Designed to match the metal-cased voltage regulator rectifier configuration used on the listed 250cc and related displacement motorcycles. Application Scope: Intended for use as a direct functional replacement part on the motorcycle models explicitly named in the product title. Installation Purpose: Enables restoration of standard system when replacing a failed or damaged voltage regulator rectifier on compatible models.