Features: The guitar effector knob is craft from quality ABS plastic, with no burrs, not easy to fade. Bottom diameter: 25mm, top diameter: 20m, height: 14.5mm, aperture: 6.4mm (1/4 "). Multiple colors are available to meet your different needs and make your guitar stand out. Suitable for electric guitar effectors, single pieced effectors, radios, speakers, etc. Equipped with fixing screws, it is not easy to loosen after installation, making it your first choice for upgrading or replacing the effector knob. Specifications: Material: ABS+Metal Color: refer to picture to selection please Size: about diameter 25mm/0.98", height 14.5mm/0.57", inner hole 6.35mm/0.25" Package Includes: 1x Guitar Effector Knob note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.