MARINE GRADE PRIMARY WIRE is tinned copper stranding for maximum protection against corrosion, electrolysis and resists fatigue due to vibration and flexing. Rated at 600 volts and 105 degrees C, the heavy duty insulation is resistant to heat an abrasion. Exceeds all UL 1426, US Coast Guard Charter Boat and ABYC standards. Gauge 18 Color Red Length 500"