The SM 2058 is an industrial-grade 24-Volt Alternator Rotor (Armature Assembly) specifically designed for the Delco Remy 24SI series. The 24SI is a high-output, brushless-style heritage design (though the rotor serves the internal excitation needs of the platform) used extensively in heavy-duty trucks, coaches, and construction machinery. This rotor is calibrated for a 4-Pin regulator interface, ensuring high-efficiency charging in demanding 24V electrical environments.