This is an 8in8out (6in6out analog) USB audio interface. It's quite old, but I've used it with affection because it's easy to use. I also own the UR series, but this one sounds better in every way, and I prefer its dedicated interface, which is easier to use. I'm selling it now because I'm switching to Mac, and the drivers aren't compatible with Mac's CoreAudio. I've used it on Windows 10 and 11. It's rock solid. It works perfectly with Amazon Music's exclusive mode for everyday listening. The MOTU M series doesn't work. Channels 1-4 have a switch to select between front and rear inputs. This is incredibly convenient. Furthermore, the rear inputs are for line-level signals, and because they bypass the mic preamps, the output is very clean and natural. It's perfect for connecting analog synthesizers, drum machines, DJ mixers, and other line-output devices. It supports up to 24bit/96kHz. Drivers can be downloaded from the AVID website. Windows users will likely be able to use it without any problems. At least in my environment, it was very stable. It's built better than recent models, and it even has a power switch. It functions as a 2in2out audio interface without AC power, and you can monitor with direct monitoring. I'll also include a third-party AC adapter as a bonus. This is a used item, so no returns or exchanges. Please refrain from purchasing if you are a complete beginner, as you may not be able to use it conveniently.