Ancor Marine Grade lugs are manufactured from heavy-duty annealed tinned copper to provide maximum current flow. This 100% tin-plated copper material resists corrosion from salt and moisture, making it perfect for use in marine environments. The seamless barrel design allows for maximum strength when crimped. The closed-end design seals out moisture so cables stay dry and free of corrosion. UL 486A. SPECIFICATIONS:• 4 AWG• 5/16" Screw• Size: 7.9mm• Pack Qty.: 25 Resists corrosion from salt and moisture Seamless barrel design for maximum strength Closed-end design seals out moisture | Tinned Copper Lugs, 4 American Wire Gauge, 5/16" Screw, 25 Pack