To purchase the rear wheel disc for the Benelli Imperiale 400 , you should look for a disc that matches the following specifications: The Benelli Imperiale 400 typically uses a rear brake disc with an outer diameter of around 240mm, though exact dimensions can vary. It is crucial to ensure the disc is compatible with your specific model year and configuration. You can check with Benelli dealerships or authorized service centers for the exact specifications and to obtain the correct rear brake disc for your vehicle.