3M Highland™ 151032 Terminals Block Fork Vinyl Insulated 12-10 AWG is UL Listed and CSA Certified for use on stranded copper (AWG) wire only. Strip away the end 3/8 inch of wire insulation. Make the crimp in the proper station of a recommended 3M crimp tool: TH-440, TH-450 (scissor style), or TR-490 (ratchet style) hand tools.