The Roland Juno 6 is a very basic single oscillator Polyphonic synth from the early 80s.
It has a characteristically thin sound and is rather well made so many examples still work. If you want one look for a Juno 60 or juno 106 because they have memories and /or midi.
Avoid the alpha Juno 1 and 2. (I have one of each... One of which I have used at every live gig for thirty years.) They don't have sliders.