Simple Electric Solutions Tinned Copper Battery Lug kits are designed with the Marine and Auto environment in mind. The closed end design and tinned copper surface of these lugs coupled with the included Dual-Wall Adhesive Heat Shrink provides an impermeable resistance to salt water and other liquids, protecting your electric connections from harsh environments. Great for Marine, Auto, Golf Carts, and misc. electrical applications. Buy with confidence as your satisfaction is 100% guaranteed.