Accepts many different wire sizes without pre-twisting Each connector is rated for up to 600-Volt Used for copper wire only Winged design provides a secure grip for easy and fast installation Wire Connector Color: Red For use with #18 to #10 AWG copper conductors Minimum Wire Range: 2 - #14 Maximum Wire Range: 5 - #12 Maximum Rated Voltage: 600V (Building Wire) / 1,000V (Fixtures and Signs) Temperature Rating: 105 °C / 221 °F Wire Strip Length: 5/8 in. Intended only for use with copper wiring (Cu/Cu Only). Not for use with aluminum wires. For use in dry locations only UL 486C Listed and CSA 22.2 No.188 Certified UL 94V-2 flame-retardant shell