6061-T6 Aluminum CU9AL Dual Rated for use with Copper and/or Aluminum wires. Insulated Splice with rugged high-dielectric Rubber/Vinyl Coating. Pre-Filled with Oxide Inhibitor. Insulated Splice provides Easy Re-entry for changes, inspection or troubleshooting. Plugs marked with connector max wire size for easy identification. One wire per terminal. 600 Volts. ANSI C119.4 & cULus 486b Listed.