Feature:1. Widely Compatible: This headphone amplifier is suitable for most 3.5mm jack headphones and for Quiet Comfort 25(QC25) headphones, for Quiet Comfort 35 II(QC35 II) headphones, for Quiet Comfort 45(QC45) headphones.2. 96KHz 24bit Sampling frequency: This external USB sound card can convert any PC or laptop into a high performance audio source. The DAC sampling frequency supports 96KHz/24bit.3. USB to 3.5mm Audio Adapter: This USB audio adapter adopts USB to 3.5mm jack audio adapter, connect headphone with 3.5mm jack to USB interface of PC or laptop.4. USB Volume Control: This external sound card is designed with knob that allows you to adjust the main volume of your PC or laptop, including the volume of any applications that are currently in use.5. Microphone Monitoring: This headphone amp is featured with microphone monitoring, thus you can hear your own voice through the headset. Press the button on the front of the controller to switch four monitoring levels, including off, low, medium and high.Specification:Item Type: Headphone AmplifierMaterial: ABSApplication: Suitable for Most 3.5mm Jack Headphones and for Quiet Comfort 25(QC25) Headphones, for Quiet Comfort 35 II(QC35 II) Headphones, for Quiet Comfort 45(QC45) Headphones.USB Protocol: USB2.0Operating Voltage: DC 5V0.3VWorking Current: <20mADAC Decoding SNR: 97dBDAC Sampling Frequency: 96KHz/24bitEarphone Driving Capacity: 16 to 150Hardware Equalizer: Bass and Treble BoostDevice Jack: 3.5mmSupported Broadcast Parameters: 8K, 16K, 22.05K, 32K, 44.1K, 48K, 88.2K, 96KSupported Audio Bit Depth: 16/24bitsCable Length: Approx. 2.5 Meters / 8.2ft ( Manual Measurement, Slight Error May Exist ).Package List:1 xHeadphone Amplifier