Specifications: Suit for DIY MARSHALL loudspeaker boxeffector, and guitar and other equipment Excellent quality, Perfect workmanship. Comfortable handfelt. Color: Black+Gold Size: Inner diameter 6mm, High 15mm, Top Diameter 15mm, Bottom Diameter 20mm Installation: fixed thread by the side Material: ABS Package included 2x Guitar AMP Amplifier Knob Note: Light shooting 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.