1/0 Gauge Wire Lugs are made from 99.9% pure annealed copper, providing a high degree of conductivity for maximum current flow. This particular variant is suitable for use with 1/0 or 0 Gauge Battery Cable & 1/2" (M12) Stud. https://selterm.com/collections/1-0-awg-bare-copper-lugs-battery-cable-ends