Closed screw type BANANA PLUG Material: copper ,Size: 4mm ,length: 45mm Surface: 24K gold plated, Color: red/black plastic ring It's accept bare wire or spades and 12 to 18 AWG speaker wires Color coded black/red rings for maintaining proper polarity Banana plugs make speaker wire installation a breeze and are great to use with A/V receivers, amplifiers, surround sound systems, banana wall plates. Material:Pure Copper, gold plated, Pure copper made, non-magnetic. Secure, positive contact with binding posts No soldering required. High quality.12 months manufacturer warranty and 24/7 hours customer service