1Easy Installation with Fixed Screws: This bass guitar tuner is user friendly and easy to install with the included fixed screws. Making tuning a breeze. 2Accuracy Engineering: Experience accurate and effortless tuning every time with our open bass tuner featuring a gear ratio of 20:1, sealed lubrication for long lasting durability, and unmatched accuracy in engineering. 3Zinc Alloy Construction: The tuner is crafted from zinc alloy, ensuring resistance to erosion and rustproof performance, and providing stable and long lasting performance. 4Open Design for 4 String Bass: Embrace the vintage vibe with this open bass tuner, designed specifically for 4 string bass guitars. 5Ideal for Accuracy and Jazz Bass Guitars: Ideal for tuning accuracy bass guitars and jazz bass guitars, this tuner ensures accurate tuning for your low end frequencies. 4 x Tuner 4 x Screw 4 x Washer 4 x Nut