Standard 3.5-mm audio headphone jack.
- Instructions: Settings > General > Accessibility > Mono Audio
- Device/Operating System : iPod Touch (4th Gen)
- Other Info (if applicable): Supports Bluetooth 2.1 + EDR (Extended Data Rate) technology. Mono Audio: route both right- and left-channel audio source material into both earbuds, enabling users to hear both channels in each ear.