Schaffer–Vega diversity system
The Schaffer–Vega diversity system (SVDS) was a wireless guitar system developed in 1975–76, engineered and prototyped by Ken Schaffer in New York City, and manufactured by the Vega Corporation, El Monte, California. A handheld microphone version was introduced in 1977.
Source: Wikipedia — Schaffer–Vega diversity system (CC BY-SA 4.0)