Item Type: Guitar String Locking Nut_x005f_x000D_Material: Metal_x005f_x000D_Size: Approx. 1.65cm/0.65in_x005f_x000D_Color: Black 16 PCS SET: The set contains 6 pcs string locking nuts, which are suitable for electric headless bass guitar, can tightly lock the strings. 2ZINC ALLOY MATERIAL: The guitar string locking nuts are made from excellent zinc alloy material, which are sturdy and firm. 3CORROSION RESISTANCE: The metal strong locking nuts are corrosion resistance, ensuring lasting durability. 4EASY INSTALLATION: The headless guitar string lock comes with a wrench and 6 mounting screws, very easy to install. 5IDEAL SUBSTITUTE: This professional headless guitar string locking nut set is ideal for replacing old broken or damaged parts.