This series connectors including 1/4″ female mono jack connectors, 1/4″ female stereo jack  and locking 6.35 mm stereo female phone connector. They are used for joining with a 1/4″ male jack connector either as part of an extender cable or an input. With its TRS (Tip, Ring, Sleeve) configuration, this connector has 3-poles and capable of carrying either a stereo or balanced audio signal. Both of which require 2 poles to send the main signals (Left, Right) or (Positive, Negative) and a remaining pole for the ground signal.