Package:12pcs Black Guitar String Through Body Ferrules Mounting Replacement Part Mateial: Size:approx 11.5mm in length Color:black as the picture show Made of premium material,durable,anti-rust, sturdy, corrosion resistant,suitable for most guitars. Guitar string caps through body ferrules mounting buckle bushing parts accessories.Easy to install and convenient to use.Great replacement for your old, broken ferrules. A good tool to make the strings vibrate more effectively, improve the resonance and increase the delay, make the sound more stronger and clear.