Headphone jack for private listening and real time monitoring. Two multifunction control buttons Minus button: volume down and MP3 music conversion key. Use this to reduce playback level and access the MP3 conversion function as described by the control design. Plus button: volume up and next song key. Use this to increase playback level and skip to the next track. Power and recording control Power switch also serves as the record switch. Turn the device on and off, and start or stop recording with a single control. Key benefits Simple, compact control layout with two multifunction buttons for efficient playback and recording management. Keeps listening private and convenient through the onboard headphone jack. Integrated controls allow quick volume adjustment, track navigation, and recording without needing additional devices. Use scenarios Field recording or interviewing: power the device on, press record to start, use the plus button to adjust volume or move to the next track during playback, and the minus button to lower volume or engage MP3 conversion as needed, then monitor audio via the headphone jack. Commuting or on the go music management: connect headphones, quickly adjust volume with the plus/minus keys, and use the plus key to skip to the next track while listening. Quick meetings or demos: power up, start recording with the same switch, and manage playback or track navigation with the two multifunction buttons while monitoring through the headphone jack.