This is an external stereo microphone for Sony Walkmans that allows for voice recording. I used it once and have been storing it at home. Operation has been confirmed. There are no instructions or box. Please consider after confirming compatibility with your device. [Manufacturer's Description Below] External stereo microphone for voice recording on Walkman You can transfer recorded data to "SonicStage" for library management, and it has a 2-level recording level switch (dictation/conference mode). The AGC (Auto Gain Control) function automatically adjusts the volume of voices for uniform recording. It has 4-level bit rate settings (ATRAC: 256/128/64kbps, PCM: 1411kbps). *Compatible only with Walkmans equipped with WM-PORT *Compatible only with Walkmans equipped with direct encoding function