The Vevor battery isolator kit is a 12V 140A split charge relay system designed to charge two batteries while helping keep the primary battery ready for vehicle starting. It includes the components needed for a complete installation and is built with a rugged nylon plastic housing for long-term use. The relay features IP65 waterproof protection for dusty, wet, and vibration-prone environments. Its compact design makes it suitable for RVs, caravans, trucks, boats, yachts, and other off-road or marine applications.