Tubular Terminal is composed of Copper and PVC. Copper (rose gold color) has better electrical conductivity and ductility compared to brass (light gold color).PVC protective sleeve, insulation and flame retardant. Different colors can also distinguish the terminal type more quickly 1200PCS Wire Ferrules Kit E0508 AWG 22 (Color:White Quantity:200PCS) E7508 AWG 20 (Color:Grey Quantity:200PCS) E1008 AWG 18 (Color:Red Quantity:200PCS) E1508 AWG 16 (Color:Black Quantity:250PCS) E2508 AWG 14 (Color:Blue Quantity:250PCS) E4009 AWG 12 (Color:Grey Quantity:50PCS) E6012 AWG 10 (Color:Yellow Quantity:25PCS) E10-12 AWG 7 (Color:Red Quantity:25PCS) Handle PP+TPR handle for more comfortable use experience. Wire Ferrules Crimping Pliers Self-adjustment to the size of wire end-sleeves crimper for insulated terminal & non-insulated ferrule. Structural Design 4 Serrated alloy Jaws are driven,the crimping takes on square shape.Range: AWG 23-7 (0.25-10mm²)