Of course, later, it was common to see a third ring to handle stereo audio. At first, the stereo plugs were given a sharper tip so it would be possible to build jacks that would not accept a mono ...
Connects two 0.25in stereo jack plugs to one 3.5mm stereo socket. End 1 = Female 1/4 in Stereo (2). End 2 = Male 3.5 mm Stereo (1). Type = Audio. Converts From Type = 1/4 in Stereo. Converts To Type = ...