The CEM3372 contains a two-input voltage-controlled mixer, a 4-pole lowpass filter, and a voltage-controlled amplifier. It’s basically an entire synth voice on a chip, minus the oscillators and envelopes.
This chip was used in several classic synthesizers, including the Sequential Prophet T8, their flagship synth at the time they went bust. It was also used in the Oberheim Matrix 12 and Xpander synths, which were the most sophisticated analog synths ever built at the time.
These are original unused vintage chips with a 8527 date code (e.g. week 27 of 1985).