Clear Insulation allows Visual Confirmation that conductor is properly inserted. In-Line 6061-T6 Aluminum Connector - CU9AL Dual Rated for use with Copper and/or Aluminum wire. Single Piece Clear Molded Insulation with Rugged High-Dielectric Plastisol Dipped Coating is chemical and abrasion resistant. Pre-filled with Oxide Inhibitor. Easy Re-Entry for Changes, Inspection or Troubleshooting.