Grover's 135 Series are tuning machines for nut-tightened guitars, featuring a 3-per-side (3x3) configuration. They have a classic shape with plastic knobs. The gear ratio is 14:1. This model is widely used not only for electric guitars but also for acoustic guitars. - Brand: GROVER - Model: 135N - Type: 3x3 (Set of 6) - Finishes: Nickel - Button: Keystone type (Plastic) - Hole Size: 25/64" (approx. 9.922mm) - Gear Ratio: 14:1 New, unused. The packaging has some minor damage. Thank you.