One Hole Aluminum Compression Lugs are AL9CU Dual Rated and accept both Aluminum and Copper Conductors. Connector Barrel is Coated with Oxide Inhibitor & capped. Aluminum Compression Lug is made of High-Conductivity Seamless Aluminum. Uniform Bright Electro-Tin Plating resists corrosion, reduces contact resistance and gives you maximum conductivity. Single Mounting Hole. Color Coded for Easy Identification.