1 Hole Long Barrel Copper Compression Lug 4 AWG - 5/16" Bolt Long Barrel Copper Compression Lugs are produced from high conductivity copper tubing. They are tin-plated to provide corrosion low contact resistance. Marked with die index and color coded for easy reference. Listed for 35KV maximum when properly installed and to cable manufacturer instructions. Temperature rating 90 degrees C. .