Vol-Button (Previous Song/Volume Decrease): In Mp3 State, Vol-Short Press Is The Previous Song, Long Press Is Volume Reduction; In The Fm State, Short Press To Adjust The Station Number Upwards; Under The Bluetooth Function, A Short Press Is A Bluetooth Previous Song, And A Long Press Is A Volume Reduction. Scan Button (Play/Pause): In Mp3 State, Scan Short Press To Play/Pause; In The Fm State, Short Press Is Play/Pause, Short Press Is Automatic Closing And Saving Station; Short Press Under Bluetooth Function To Play/Pause. Vol+ Button (Next Song/Volume Increase): Vol+ Short Press Is The Next Song In Mp3 State, And Long Press Is Volume Increase; In The Fm State, Short Press To Adjust The Station Number Down; In The Bluetooth Function, Short Press Is The Next Song Of Bluetooth, And Long Press Is Reduced Volume. Mode Button: Switch Between Usb / Sd / Fm / Audio Input / Bluetooth Function. Long Press 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