4MM Banana Plug / Charge Plug is High-quality cage spring plugs. The nickel plated brass, plug body is fitted with a beryllium copper cage spring. The insulation being molded in polyethylene. The plug body accepts cables up to 4mm diameter.

The plug has one or more lengthwise springs that bulge outwards slightly. It presses against the sides of the socket, improving the electrical contact and preventing the pin from falling out.