Multiple Wire Gauges: The 5/16" allen hex insulated connectors are specially designed for 250MCM-6AWG wires Insulation Material: Aluminum wire connectors are insulated with high dielectric strength plastic sol for improved chemical protection and wear resistance Mixed Connection: 3 Port insulated tap connectors allow aluminum wire to aluminum wire, copper wire to copper wire and copper wire to aluminum wire connections, making the insulated connector the best alternative for safely splicing aluminum wire to copper wire Product Features: Black insulated connectors can be easily reinserted for inspection and troubleshooting. It uses hex screw to fix the wires and comes with lubricating oil with antioxidant properties in the ports. Aluminum connectors are safer and more convenient than butterfly nut connectors, with larger wire diameter range and higher current Unique Design: The design purpose of splicing electrical power connectors are to ensure the safety of aluminum to copper connections and to prevent problems caused by aluminum wire overheating due to wire mixing Multiple Wire Gauges: The 5/16" allen hex insulated connectors are specially designed for 250MCM-6AWG wires Insulation Material: Aluminum wire connectors are insulated with high dielectric strength plastic sol for improved chemical protection and wear resistance Mixed Connection: 3 Port insulated tap connectors allow aluminum wire to aluminum wire, copper wire to copper wire and copper wire to aluminum wire connections, making the insulated connector the best alternative for safely splicing aluminum wire to copper wire Product Features: Black insulated connectors can be easily reinserted for inspection and troubleshooting. It uses hex screw to fix the wires and comes with lubricating oil with antioxidant properties in the ports. Aluminum connectors are safer and more convenient than butterfly nut connectors, with larger wire diameter range and higher current Unique Design: The design purpose of splicing electrical power connectors are to ensure the safety of aluminum to copper connections and to prevent problems caused by aluminum wire overheating due to wire mixing