- 360° Rotatable USB Computer Volume Controller This usb volume knob features a 360° rotatable knob for precise volume adjustments and a one-touch mute function, providing convenient control over your computer's audio output. - BT USB Volume Knob for PC Equipped with BT 5.1 Chip, this volume control for pc allows you to effortlessly pair your computer with BT-enabled headphones or speakers, ensuring a seamless and quick connection for wireless listening. - USB Decoding Player This U disk player supports a wide range of audio formats including MP3, WAV, WMA, APE, and FLAC. It also features fast forward, rewind, and folder switching for enjoying your music in various ways. - External Sound Card Adapter In external sound card mode, you can plug your headphones into the 3.5mm headphone jack to listen to your computer's sound without having to crawl under the desk to find the headphone jack. Use scenarios - In the office or at home, quickly adjust volume and mute during calls or video conferences without reaching for the computer. - Enjoy wireless listening by pairing BT headphones or speakers for music, movies, or games, then control volume from the knob. - Play audio from a USB drive with built-in decoding, and navigate MP3, WAV, WMA, APE, or FLAC files with fast forward, rewind, and folder switching.