All Perkins alternators 2871A306 have been specifically designed to work with the power and speed of your engine, to ensure a durable and long life, and tested for thousands of hours on an engine to maximize operating life and ensure durability. As we use the latest technology components, you can be sure of reliability and performance and are the same parts supplied with your genuine engine. Perkins alternators are designed to fit on our engines, with mountings in the same orientation and place as on the genuine engine, making replacement an easier task. A non-genuine alternator may not have the mounting/fittings making replacement harder and weakening performance and lifetime or the power to keep up with all of your machines electrical requirements. Repaired or rewound electrical parts may not have the durability of a new genuine part, and can cause early failures from poor quality internal brushes and bearings.