This is a set including the main unit and the AC adapter for Zoom. I was using it until recently, and its operation has been confirmed. I have also confirmed that it powers on with the adapter before listing it (see image 2). I've been fond of it for several years, using it a few times a month, but I've replaced it with a new one and no longer need it. I'd like to pass it on to someone who can use it. Please read my profile before purchasing.