3.5mm male to 2.5mm male stereo 28AWG FT4 - BlackThis ultra slim stereo audio cable has a 3.5mm male on one end and a 2.5mm male on the other. It is typically used to connect 2.5mm mobile devices such as some MP3 players and smart phones to 3.5mm stereo inputs. The ultra slim connectors and cable are designed to be light weight, durable and fit perfectly in mobile devices. They also work with most protective cases.