A gift from my aunt, who retired it in favor of an APS camera of some sort. That and you can't get film for it anymore; Kodak quit making the discs in 1999. And the batteries are dead.
When Kodak introduced the Disc system in 1982, there were four cameras, the 2000, 4000, 6000 and 8000, in ascending order of price and features. The 2000 was not meant for the US: it was the very basic machine, and it used a 9v battery. This 4000, therefore, was the base model. Instead of a 9v battery it had lithium cells which "never had to be replaced by the user." Which really meant that you had to send the camera back to Kodak to have them do it, which costs money. If you're not faint of heart (and since it's now a filmless classic), you can pop the case open and see the two batteries. I have no idea whether you can get a proper replacement for them.
As this is the base model, there's not much to it. It's got a bare metal-like finish and no cover. There's a slide switch which shifts the lens cover in and out of place, and there's the shutter button up front. That's it. The only other thing is the lever on top which opens the back so you can change the film cartridge.
In 1984, this was retired and replaced by the Disc 4100.