【Product Standard】Black Insulated in-Line Splice Connector Suitable for 2/0-6AWG copper wire and 2/0-4AWG aluminum wire. The size of the hex screw used for fixing is 3/16″. Insulated throughout with high dielectric strength rubber and vinyl coating for copper and aluminum wires, and prepped with internal lubricants for oxidation resistance, insulated connectors are designed to withstand temperatures from -49 to 194 degrees Fahrenheit, and the 600V cable conductors are aluminum CU9AL dual rated for copper and aluminum wires. Leia Mais