This heavy-duty 12V 200A battery isolator relay is an essential component for managing dual battery systems in vehicles, RVs, boats, and other automotive applications. Designed with a universal 4-pin configuration, this relay switch provides versatile installation options and compatibility with a wide range of 12-volt electrical systems. The high current capacity of 200 amps makes it ideal for demanding applications that require reliable power distribution and battery isolation. The relay features a compact and durable construction with copper terminals and a robust housing that ensures long-lasting performance even in challenging conditions. The clearly marked pin diagram (30, 86, 85, 87) simplifies wiring and installation, making it accessible for both professional mechanics and DIY enthusiasts. This relay effectively isolates your auxiliary battery from your main battery, preventing discharge when the engine is off while allowing charging when running. Perfect for powering accessories, winches, audio systems, and other high-draw equipment without compromising your starting battery. The relay measures approximately 2 inches in length, 1.2 inches in width, and features a convenient mounting bracket for secure installation.