• Manufactured from high strength copper alloy. Provides maximum conductivity and high breakage resistance.• Electro-tin plated bolt, nut, spacer and pressure bar. Provides low contact resistance.• Precision tooled threads allows maximum torque to be applied.• UL Listed and CSA Certified.• Suitable for use in circuits rated 35KV or less; proper high voltage spacing and insulation techniques must be used.• For use with copper conductor types: Solid, Compact, Compressed, Concentric.• SK-6,SK-4, SK-3, SK-2 are UL listed AL9CU.• For other aluminum applications consult factory.• SK-10, SK-8, SK-3, SK-2, SK-1/0, SK-2/0 are RUS Accepted.• ROHS compliant.• UL File E12822