This Goodall by Vanair 12 Volt, Heavy Duty Anti-Zap Surge Protector is used to protect a truckselectrical system while welding. There is an LED indicator located at bothends. The green LED indicates the correct connection and anti-zap surgeprotections, while the red LED indicates an incorrect connection and noanti-zap surge protection. Heavy Duty weatherproof and shockproof housing Crimped, tin plated, heavy gauge solid copper lugs Heavy duty 8 gauge cables