Features: It is very suitable for guitar bass and amplifier part replacments. Wonderful replacements for old damaged guitar control knobs. Great guitar tools which can provide help in guitar replacment. Made of material, the knobs is durable and long lasting use. The inner middle hole diameter is about 5.9mm, easy to use and install. Specifications: Material: Plastic Color: White/Red/Black Package Weight: approx.20g Size: approx.1.6x1.6x1.6cm/0.62x0.62x0.62in Inner Hole Diameter: approx.5.92mm/0.23in (More Size Detail, Please See Photo.) Note: Please allow 1-3mm error due to manual measurement. Please make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thanks! Package includes: 3Pcs Guitar Volume Tone Control Knobs 1Pc Hex Wrench