Available as an assembled Module and as a DIY project.
This Module is currently available.
bmc053 4 quadrant multiplier and panner
This module is a specialized VCA that can act as a Four-Quadrant Multiplier (sometimes referred to as a "Ring Mod") or as a panner. The main difference between a 4QM and a standard VCA is how it reacts to negative control voltages. A standard VCA will output zero volts, whiles a 4QM will output an inverted signal with voltage proportional to the input voltages.
https://synthcube.com/cart/bmc052-4-quadrant-multiplier-and-panner?search=panner&description=true
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These merchants probably sell this module. Huh?