Description: 4 Pieces Guitar Volume Control Button Tunning Knobs Used to replace the dirty dingy and old knob Great for electric guitar and bass potentiometer Easy to install and use Material: Metal Color: Chrome Size Chart: D: Approx. 16 7mm/0.62 x 0.66inch Package Includes: 4 Pieces Volume Knobs Note: Due to the difference between different monitors the picture may not reflect the actual color of the item. Due to manual measurement there may -2mm error in size.