Check the listing for details. 3Pcs Aluminium Potentiometer Knobs 1/4" Volume Tone Control Top Hats Black. Condition: New. Listed at 15.81 USD. What is this?Aluminum knob covers are designed for studio mixers, synthesizers or amplifiers equipped with 6mm potentiometer shafts. Top hat design suitable for most guitars and bass, commonly applied to guitar, bass, power devices or other audio equipment with 1/4" shaft potentiometers.What will I get?In the package of: 1 x Aluminium Potentiometer Knobs(Each package contains 1 x L-type hexagonal wrench: 1.5x18x51mm, Silver)Inner diameter: 6mm / 1/4 inchOuter diameter: 19-24mm / 0.75-0.95 inchHeight: 14.5mm / 0.57 inchColor: BlackAre there any advantages of the product?1. The knobs are beautifully made, with a smooth surface, no burrs edges, and all-aluminum knobs without any plastic inserts;2. The aluminum knobs are wear-resistant and oxidation-resistant, durable and can adapt to different application situations;3.