Sony USB DAC built-in amplifier. This product can be connected to a PC to play high-resolution audio such as DSD and 192kHz/24bit. I received this from an acquaintance, and it can play 96kHz and 192kHz FLAC high-resolution files without any problems. However, DSD playback didn't work well on my Mac, and it was played back as 192kHz (according to my acquaintance, it worked fine on their Windows PC). It's probably a compatibility issue between the Mac OS and the Sony USB driver. The main unit has some signs of use. There are also scratches on the rear panel. Everything in the photos is included. Please check the condition in the images. To prevent any problems, please refrain from purchasing if you are a perfectionist or have particular concerns. The following is a quote from the manufacturer's website: Amplifier Output Effective maximum output (JEITA 10% 1kHz 4Ohm): 23W + 23W ● Audio Input: Optical 1 system, Coaxial digital 1 system (gold-plated), Line (RCA) 1 system (gold-plated), USB Type A front x 1, USB (Type B) rear x 1 ● Audio Output: Headphone 1 system (gold-plated), Line (RCA) 1 system (gold-plated) ● Speaker impedance: 4-16Ω ● Frequency response: 10Hz〜100KHz (+0dB, -3dB) ● S/N ratio: 100dB ● Power consumption: 40W ● External dimensions (width x height x depth mm): 225x74x262 ● Weight: 4.0kg