This heavy-duty 500A DC 12V SPST auto start contactor relay is engineered for demanding automotive and marine applications. Built with a robust water-resistant black phenolic plastic housing, this relay serves as a high-current battery starter switch with reliable performance. The unit features silver-tin alloy contacts rated for 500 amps and operates at 12V DC, making it ideal for high-power switching applications. With a mechanical life expectancy of 10 million operations and electrical durability of 100,000 cycles at 30 operations per minute, this relay delivers long-term dependability. It includes a sturdy mounting bracket for secure installation and operates effectively in temperatures from -30° to 80°F. The relay's specifications include a 50ms operate/release time, 100mΩ minimum insulation resistance, and built-in protective features. Weighing 8.3 ounces, this compact but powerful relay helps prevent primary battery discharge and is suitable for dual battery setups. Its versatile design makes it compatible with various 12V applications where high-current switching is required.