This is the RSDA 302P from Rustem Systems. It's the "RSDA202," which once shocked the world by beating a famous top-brand amplifier costing 3.3 million yen in a blind test in the monthly Stereo magazine. This is the "RSDA302P," a higher-end model that inherits that legend and supports optical input. This is a gem recommended for those who are particular about sound quality, created by the predecessor company of Amrec. Model Name: RSDA302P Output: 30W+30W Frequency Response: 20Hz - 20KHz Front: Power switch, Volume, Treble, Bass Rear: Line input, Optical input, Speaker terminals, Power connector Accessories: Power adapter, Manual This is being sold due to equipment replacement and was working without any problems until just before. If you have any concerns about the condition of the product, please feel free to ask before purchasing. Please read the description and profile, and if you have no questions, you can purchase it immediately.