The Moog Polymoog 203a is a polyphonic analogue synthesizer used by Prince on For You and Prince. It is mentioned in the credits to For You (as "Ms Poly Moog") and appears in the I Wanna Be Your Lover video. It was also used live by Gayle Chapman and Lisa Coleman.
Polyphonic synthesizers — those had just started happening. They had the Polymoog, but it had only been out a year, two years tops. They were pricey, and they didn’t do a lot yet. The Oberheim four- or eight-voice SEM — they were called the SEM Module versions, basically equivalent of a Minimoog, which you could only play one note at a time on... He had all this state-of-the-art gear when I went into that audition.