When playing music, LEDs indicate the current sampling rate (96/48/44kHz). By pressing a button you can choose between three different equalizer profiles, indicated by the flashing LED. After selecting the appropriate EQ profile, the LED returns to the current sampling rate. The integrated microphone means that every headphone can also be used for making phone calls. The adapter is suitable for headphones with 3.5 mm audio jack and costs 30 Euro. System requirement is Windows 7 or newer, Mac OS 10.8 or higher or Android 7 or higher.