The 4mm banana plug is made of gold-plated brass, which has high strength, low resistance, conductivity, and stable mission. Built in stainless steel snap spring design firmly secures wires, ensuring safe wire connections and preventing them from falling off. The shell is made of nylon PA6 and has a flame-retardant grade of V0. Engineering plastic materials are not easily discolored or deformed. The shell is to high temperatures and is not conducive to ignition in the event of a wire fire. It has a long lifespan and is to aging. Instructions: Prepare a banana plug and wire, open the plug button, align the wire with the socket, insert the wire into the bottom, and the button to complete the wiring. Simple, practical, and time-saving. Wiring range: 0.2-2.5 square wires. Voltage/current:250V/32A Color:Black & Red Material:Plastic+Copper Package Contents: 8 * red plug wire connectors 7 * black plug wire connectors Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.