WIDE APPLICATION: USB volume control knob is compatible with multiple systems, supports Android, and is compatible with mobile phones, tablets, laptops, and desktop computers. FUNCTIONS AND USES: USB volume controller can directly control volume of computer, can be customized, supports shortcut keys. (Note: Custom functions require editing software; please contact customer service for editing software.) 2.4G + Bluetooth + Wired Version: The three-mode model supports wired connection, Bluetooth connection, and 2.4G connection. When connecting via Bluetooth, the main device must have Bluetooth functionality. 2.4G connection requires the receiver; simply plug it in for automatic pairing. Built-in large-capacity lithium battery with charging function. EASY TO USE: No drivers or software installation requiredplug and play operation. Customizable knob: The knob can be defined as any keyboard key, or configured for volume up/down, previous track, next track, play/pause, mouse wheel, etc. Item Type: USB Volume Control Knob Features: Customizable; Supports shortcut keys Compatibility: Android systems, laptops, desktops, tablets How to Use: 1. Rotate left: Volume down 2. Rotate right: Volume up 3. Press the knob: Play/Pause 4. Press and rotate left: Previous track 5. Press and rotate right: Next track Color: Black Material: ABS + Acrylic Package Contents: 1 x USB Volume Controller 1 x Data Cable 1 x 2.4G Receiver Note: Light reflection and different displays may cause the color of the item in the picture to vary slightly from the actual product. Measurement error allowance is +/- 1-3 cm.