Copper lugs with 5/16 inch eyelets are for attaching cables to a 5/16 inch stud or bolt such as is commonly found on battery terminals. These copper lugs are made from pure copper tubing. The cable end is flanged for easier cable insertion. The lugs are used for electrically terminating power and battery cable sizes 6 gauge through 4/O gauge. The copper lugs can be soldered using standard electrical solder, or you can use our convenient solder slugs, with solder and flux in a single pre-measured pellet. The lugs can also be crimped using a hammer crimper, or our Jr. Hex Lug Crimping Tool.