Highland™ 054007-43136 H-33 Fully Insulated Twist-On Wire Connector, Ribbed Shell Style, Round Spring, 18 to 12 AWG Wire, Aluminum/Copper Wire, Steel

3M™ Highland™ Color-Coded Wire Connectors make it quick and easy to match the right connector to the size of the wire. The shells are designed to withstand temperatures up to 221 deg F (105 deg C). Highland color-coded wire connectors are UL Listed, CSA Certified, and work equally well with either solid or stranded copper wire.