3M™ Scotchlok™ Color-Coded Closed-End Connector Is An Electrical Crimp Sleeve Connector With A Copper Insert That Allows For Fast Splicing Of Copper Conductors. The Vinyl-Insulated Connector Is 600V-Rated For Building Wire and 1000V-Rated For Signs, Fixtures or Luminaires. It Withstands Temperatures Of -40 to 221 Degrees F (-40 to 105 Degrees C).