Audio Adjuster USB Volume Control Knob Replacement Non Slip Pad Metal for OS X for Win 10 8 7 Feature: 1. Support one key mute function, just pre the knob to enter the mute state immediately, pre again to restore the sound, simple and convenient to use. 2. USB connection, plug and play, once connect computer power, you can turn the knob to easily and quickly adjust the computer's volume. 3. Metal shell, non slip pad at the button, sturdy and durable, have a long service time. 4. Have wide application, a computer volume control knob to watch videos, play games, etc. 5. With stable and excellent performance can be used to replace old or damaged volume control knob. Specification: Item Type: USB Volume Control Knob Colour: Black Material: Metal Product Application: This external volume control knob is specially designed for computers and is compatible with for Win 10 8 7, for Vista, for XP, for OS X. Package List: 1 x USB Volume Control Knob 1 x User Manual 1 x Connection Line How to use: Theknobadjuststheupanddownvolume,pretheknobtomute,preandholdtheknobtoadjustthevolumefaster;pretheknobfor8seconds,enterthenightmode,thebreathinglightkeephining.