The Napa Echlin ST26 Starter Solenoid Switch is a vintage part designed for Hudson, Rambler, Nash Ambassador vehicles, operating on a 12V system. It is a direct replacement part manufactured in China, featuring a matte finish. The solenoid switch is an OE/OEM part with interchangeable part numbers S42, 1S5204, DR450, and 15122, and manufacturer part number SW26. While not noted as a performance part, it serves a critical function in the vehicle's ignition system. Additionally, the product comes with a California Prop 65 warning for potential cancer and reproductive harm.