Ring terminals are tinned copper for maximum corrosion resistance and greatest electrical conductivity. Grooved barrel grips wire to provide superior holding power and current flow. The nylon insulation resists sunlight, gasoline, oil and chemicals - will not punch through. The crimp ridge positions the crimp to prevent mis-crimps. Brass sleeve crimps on wire insulation to provide fatigue and strain relief. Funnel entry guides wire into position and prevents strand turn back. UL Listed.