Alternator 120 AMP 12V 4" Dual Foot Saddle K6 Pulley with Isolated GroundAlternator, 604 Series, 120A, 12V, Saddle Mount (Dual Foot), 4in, K6 Serpentine Pulley, Isolated Ground 4" J-180-Style Mounting;  Typical for Caterpillar, Cummins, Detroit Diesel & John Deere EnginesReplaces: 604-120-SR-IGThis product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns. The Balmar Alternator you mentioned is a 120 Amp, 12V alternator with a 4" diameter, dual foot saddle, and a K6 pulley. It also features an isolated ground. Here are some details about this alternator: Amperage: The Balmar Alternator has a maximum output of 120 Amps, which means it can provide up to 120 Amps of charging current at 12V. Voltage: The alternator is designed for use with a 12V electrical system, commonly found in many vehicles and marine applications. Dual Foot Saddle: The alternator is designed with a dual foot saddle, which provides a secure mounting option for installation. Pulley: The alternator comes with a K6 pulley. The "K6" designation refers to the specific pulley size and configuration, which determines the belt size and compatibility. Isolated Ground: The alternator features an isolated ground, which means the ground connection of the alternator is electrically isolated from the chassis or engine block. This can help reduce electrical interference and improve performance in certain applications. The Balmar Alternator is commonly used in various applications where a high-output alternator is required, such as marine vessels, RVs, or other vehicles. It is designed to provide reliable charging power to the electrical system.