Copper Mechanical Lug, 1 Hole, 1 Barrel, Fixed Tongue, No. 14 - No. 4 American Wire Gauge (AWG), 1/4 Inch (6.4 mm) Stud, Made from high strength electrolytic copper to provide premium electrical and mechanical performance, Compact design saves space, Inspection window to visually assure full conductor insertion, Plated steel set screw provides high strength, durable electrical contact between conductor and connector, UL Listed and CSA Certified for use up to 600 Volts.