This is an RCA plug for audio use, a virtual ground, made entirely with 1960s Western Electric internal wiring. Set of 2. These are very popular. They use the same wire as the vintage Western Electric grounding wire for turntables, and are directly connected to the internal ground without using terminals. Connecting these to unused RCA input terminals on your pre-amp, main amp, etc., will prevent noise from entering through the unused terminals and provide the unique sound of vintage Western Electric. You can enjoy the high-frequency clarity, the deep bass, and the high sound resolution, along with the sound of the vintage wire. These are virtual grounds that can also be made with TS plugs.