For waterproof splicing of submersible pump cable and other underground UF cables. Copper wire range 8 to 14 AWG. Special brass connector is used to make a solid splice. The mastic-lined heat-shrinkable tubing is used over the connector for a complete waterproof splice connection. 600 volt rating 105 deg (degrees) Celsius, 221 deg Fahrenheit. UL (Underwriter's Laboratories) listed.