Features: brand new and high quality Wonderful usage experience: Rotate the Multimedia knob to adjust the volume.With one for key mute function, just press the knob when you are listening to music, the music will be stopped and start playing if pressing the knob again. Bluetooth-compatible transmitter for pc: Convert the computer audio signal into Bluetooth-compatible audio signal, connect with bluetooth-compatible headset, and add wireless function for the computer. Bluetooth-compatible transmitter mode: green light on:It can connect one Bluetooth-compatible devices , such as Bluetooth-compatible headsets/speakers. Not applicable for/mice/ keyboards/ for Mac OS, Linux, TV, Car Stereo. Non-slip design: Anti-slip mats stick to the bottom , this volume controller is pretty steady. Not easy to move. Driver Free: This volume control knob supports for Win10/8/7/for Mac, Plug and for play, no driver required, you can directly adjust the volume by rotating the knob.Easy to carry and use thanks to its mini exquisite design. Specifications: Material:ABS Colour: Black Size: Approx. 3.7x2.5x1.3 inches Weight: 182g Note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Volume Control Knob