This heavy-duty 12V 200A battery isolator relay is an essential component for managing dual battery systems in automotive, marine, and RV applications. Engineered to handle high current loads up to 200 amperes, this universal relay provides reliable power distribution and protection for your vehicle's electrical system. The 4-pin configuration features clearly marked terminals (30, 86, 85, 87) that simplify installation and ensure proper connectivity. Its compact dimensions of approximately 2x1.2x0.4 inches make it easy to mount in tight spaces, while the durable housing protects internal components from vibration, moisture, and temperature fluctuations. The relay functions as an intelligent switch that automatically isolates your auxiliary battery from the starting battery, preventing drain and ensuring you always have power to start your engine. Copper terminals provide excellent conductivity and corrosion resistance for long-lasting performance. Whether you're upgrading your car's electrical system, installing auxiliary power for camping equipment, or setting up a marine dual battery configuration, this relay delivers the robust switching capability you need. The unit meets CCC certification standards and is designed for straightforward installation with standard automotive wiring practices.