Ancor's Marine Grade terminals differ from automotive terminals by being designed specifically for the harsh marine environment. Nylon insulators are easy to crimp and will not split. The barrels are designed to tightly grip the wire with the least effort. The double-crimp, funnel-entry design guides the wire into position and prevents strand turn-back. Tinned copper offers the least electrical resistance while providing the most corrosion protection. UL 486C.