product description:support MP3 format, power automatically play, play the status of the red LED update.support U disk (tested over 32G), TF card (tested 16G) playback mode; power default TF card mode, if the TF card does not exist automatically jump to U disk mode, and both devices are installed, you can manually Set the playback mode, please refer to the key operation instructions.button to adjust the up and down track switch, volume + -, pause / play, mode switch, Note: "long press" time about 2SIf you use U disk mode, the proposed 5V power supply, some U disk does not support 3.7V power supply.Product specificationsPower supply range: 3.7 ~ 5.5VProduct Size: 45mm * 36mmExquisite double board design, area copper, stable and reliable.Anti-static bag refined packaging, to avoid damage to the way of delivery static electricity.Material: metalcolour: bluePackage Include: 1 x Mp3 lossless decode boardNote: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.