MATERIAL: Durable hard acrylic, ABS plastic and steel. PACKING: 6 guitar string tuning nails, 6 ferrules, 6 mounting screws. SOUND QUALITY: Keep the guitar tuning simple and accurate, mainly used for 6-string classic guitars (electric or acoustic). FUNCTION: These guitar tuning nails are perfect replacements for old and tuning nails. These guitar tuning nails have high sound quality through many tests. Gear ratio: 1:14, with heavy duty internal gear, fit 10mm (0.39inch) standard machine heads hole. Color: Silver Material: zinc alloy Package Contents: 3 x left guitar string tuning nail 3 x Right guitar string tuning nail 6 x ferrule 6 x screw fittings Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.