Vol-Button (Previous Song/Volume Decrease): In Mp3 State, Vol-Short Is The Previous Song, Long Is Volume Reduction; In The Fm State, Short To Adjust The Station Number Upwards; Under The Bluetooth Function, A Short Is A Bluetooth Previous Song, And A Long Is A Volume Reduction. Scan Button (Play/Pause): In Mp3 State, Scan Short To Play/Pause; In The Fm State, Short Is Play/Pause, Short Is Automatic Closing And Saving Station; Short Under Bluetooth Function To Play/Pause. Vol+ Button (Next Song/Volume Increase): Vol+ Short Is Song In Mp3 State, And Long Is Volume Increase; In The Fm State, Short To Adjust The Station Number Down; In The Bluetooth Function, Short Is Song Of Bluetooth, And Long Is Reduced Volume. Mode Button: Switch Between Usb / Sd / Fm / Audio Input / Bluetooth Function. Long Is The Recording Function, And The Recording Audio Source Is Input To Line In. Radio Fm And Bluetooth. When Recording, You Need To Connect A Storage Device, Such As A Usb Flash Drive Or Tf Card Type: MP3 Decoder Board Model: JQ-D122BT Function: Bluetooth Decoder Colour:As Shown Material:ABS+FR4 Size:11.2 x 2.5cm Package Contents: 2 x Decoder Board 2 x Remote Control 2 x Cable Only the above package content, other products are not included. Note: Light reflection 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.