【High Quality Banana Jacks】Metal material and hex nut is brass. Nickel plating on the banana plug improves corrosion resistance and enhances surface aesthetics. Good conductivity and continuous stability. Insulation materials is PA (More resistant to high temperature than ABS plastic shell) ! | 【Connection Method of Banana Socket】Rating is 30Vac-60Vdc/Max.24A. These banana jack sockets require soldering or crimping. Specifically, the sockets are designed to fit 4.8 mm spade crimp terminals, and also allow to be soldered connections.They are also for mounting to a panel and diameter of mounting hole is 8.0mm. | 【Fully Disassembled and Easy Connection】Come with a brass nut and a washer per binding post to attach to your panel. Great for DIY projects or as a replacement for an old or worn jack socket. You can test these 4mm female sockets with several banana plugs and test leads and they all will fit well! | 【Versatile Banana Plug Socket】The banana plug female is suitable for building test bench power supplies or Installing on your DIY speaker. Their main use would be for all types of test equipment and other electronic devices. Used for banana socket panel / chassis mount or non-insulated 4mm banana plug. | 【Color Coded Banana Jacks and Plugs】:You will get 5 black and 5 red banana plug connectors, Color coded adapters for easier recognition and quick connection. Compact banana jack for mounting in tight spaces. Mounting ring is a neat idea and the hex shaped nut are easy to tighten by hand. ( no needs a special wrench)