Features: It is make of plastic, durability, and can be used for a long time. Widely used as electric guitar effect pedal knobs, potentiometer knobs, volumes amp knobs, etc. The Guitar pedal knobs will come with a wrench to make the 6.35mm knobs tightly fit your pedals. Easy to install and use, just insert the pedal head into the hole of the guitar potentiometer and tighten the screw. Great for upgrade or replacement part. Specifications: Materials: Plastic Color: Gray White/Black/Redness/Yellow/Blue/Clear/Coffee Diameter: about 19mm/0.75inch Height: about 14.5mm/0.57inch Mounting Hole Size: about 6.35mm/0.25inch Note: Please allow 1-2cm errors due to manual measurement, make sure that you not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 10pcs Effect Pedal Knobs 1pc Wrench