I accidentally purchased this, so I opened the package, but it has never been used. The following is a reprint: Features: Ideal for custom builds where you want multiple controls in a limited space. Vintage-style concentric knobs allow for two functions (e.g., volume and tone) on a single pot. Specifications: ■ Stack Knob ■ Black ■ Inch Standard ■ Inner Diameter: ・Bottom: 6.75mm / Top: 4.7mm ■ Outer Diameter: ・Bottom: Approx. 25mm / Top: Approx. 19mm ■ Height: Approx. 23mm ■ Compatible with: EP-4585-000 and EP-4586-000