Function and parameter tips: The stand-alone card version requires a TF card to be used. With Bluetooth function, it can only connect Bluetooth headsets and Bluetooth speakers, but cannot connect to mobile phone Bluetooth. The computer connected to MP4 can only support Windows 7 system and does not support Apple system. Android phones need to have OTG function to connect, which is not supported by Apple system. Smartphones with OTG function can use the OTG adapter link to download music in MP3 format. MP3 music and video format support tips: Audio format support: MP3 format. Video format: The plug-in card version supports AVI. Downloading videos requires a conversion tool to convert the video format:. Storage capacity: supports up to 128G card Does not support FM function Maximum output power: 18mW*2 Frequency response range: 20Hz-20KHz Signal-to-noise ratio (dB): 90 Total harmonic distortion: less than 0.05% Battery type: built-in lithium battery (built-in) Screen size: 1.8-inch color screen Play time (hours): about 6 hours Standby time (hours): more than 24 hours Audio format support: wav/mp3 Supports listening to music, watching videos, audio recorder (wav), and e-books (txt format) 3.5mm audio jack Input: 5.0V, 500MA 600MAH battery Machine specifications and dimensions: 90mmX38.8mmX8.5mm Support multiple national languages: The stand-alone card model supports 6 national languages: including Simplified Chinese and English.