ITEM NAME:4x Iron Guitars Volume Tone Control Knobs Caps with Wrenches Luthier Tools Description: - 4pcs Skull Pattern Guitar Volume Tone Control Knobs - New design, more attractive - Great for electric guitar/bass - Easy to install and use - With allen wrenches - Material: Iron Size Chart: Mounting Hole Diameter: 6mm/0.23inch Package Included: 4 Pieces Control Knobs 2 Pieces Allen Wrenches 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 be 1-2mm error in size..With allen wrenches. 2 Pieces Allen Wrenches. - Material: Iron. Due to the difference between different monitors, the picture may not reflect the actual color of the item. - Easy to install and use.