EverStart 9-Piece Ring Connectors, yellow insulation sleeve made with PVC plastic, metal plate made with purple copper. One sales package contains 9 pieces ring connectors, which conforms to Model RV5-10/12-10 AWG. UL LISTED for stranded copper wire only. 600 volts maximum building wire. 1000 volts maximum in signs, fixtures and luminaries. Operating temperature: 221℉-105℉ maximum Used with stranded cooper wire only. Can also be used with 6 and 12 volt electrical systems. Crimp with crimping tool. Caution: Make sure battery or power source is disconnected before installing or removing connector. 1.Select correct connector for wire size and application. 2.Strip away the end 3/8" of wire insulation. 3.Insert stripped wire into barrel of connector and crimp. EverStart 9-Piece Ring Wire Connectors, Model 5108, Yellow,UL Listed * For use with 12-10 gauge wire,stud size 3/8" * Great for grounding * Easy wire insertion