This heavy-duty SPST relay harness is engineered for reliable performance in demanding automotive and marine applications. Operating at 12V DC with a robust 40A capacity, it features color-labeled wires for straightforward, error-free installation. The compact design incorporates premium silver alloy contacts that deliver exceptional switching reliability and durability through 100,000 electrical operations. With a wide operating temperature range from -55°C to +70°C, this relay maintains consistent performance across diverse environmental conditions. The unit's low power consumption of 1.8W and high sensitivity make it ideal for protecting electrical circuits in trucks, vans, motorcycles, and boats. Technical specifications include fast response times with 15ms operate time and 10ms release time, while maintaining impressive insulation resistance of 100MΩ at 500VDC. The sealed construction ensures reliable operation in varying humidity conditions from 35% to 80%. This relay module provides essential circuit protection while offering the durability and performance needed for automotive and marine electrical systems.