Open screw type Banana Plug accept bare wire or spades , accept 18 to 12 AWG speaker wires Color coded black/red rings for maintaining proper polarity/ First way installation 14 & 16 gauge speaker wire has to fold the wire over, then tighten the banana plug,it will not affect the sound quality. Secure, positive contact with binding posts Material: copper Size: 4mm length: 45mm Surface: 24K gold plated No soldering required, HIGH QUALIT