This heavy-duty JD1912 SPST relay harness system is engineered for reliable performance in 12V DC automotive and marine applications. Featuring color-coded wires for foolproof installation, this 40A relay comes with premium Ag alloy contacts that ensure consistent operation through 100,000 electrical cycles. The compact design operates efficiently with a low power consumption of 1.8W while maintaining high sensitivity and robust contact load capacity. With an operating temperature range of -55°C to +70°C, this relay is built to withstand demanding conditions. The system includes sealed protection and offers rapid response with a 15ms operate time and 10ms release time. Perfect for trucks, vans, motorcycles, and boats, this relay module provides the durability and reliability needed for critical electrical systems. The harness sockets are designed for straightforward connectivity, making it an ideal choice for both professional installers and DIY automotive enthusiasts working on electrical control applications.