1. Vol - Button (Previous Song/Volume Decrease): In Mp3 State Vol - Short Press For The Previous Song, Long Press For 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. 2. Auto Button (Play/Pause): In Mp3 State, Auto Short Press Is Play/Pause; In The Fm State, Short Press Is Play/Pause, And Long Press Is Automatic Closing And Saving Station; Short Press Under Bluetooth Function To Play/Pause. 3. Vol+ Button (Next Song/Volume Increase): Vol+ Short Press Is 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 Song Of Bluetooth, And Long Press Is Reduced Volume. 4.Mode Button: Switch Between Usb / Tf / Radio Fm / Audio Input Line In / Bluetooth Function; Long Press Is To Record The Microphone, And Another Long Press Is To Stop Recording And Play The Recording; Microphone Description After Connecting The Microphone, All The Microphone Functions Are Available Under The Mold Test; Description Of The Recording Function When Recording, It Is Necessary To Connect A Storage Device, Such As: U Disk Or Tf Card; Connect The Microphone Function; Power Amplifier 2 x 5w, Can Be Connected To 2 5w Speakers At The Same Time; Dual Decoding Support Mp3, Wma, Wav, Flac, Ape Lossless Format Music; Support Recording Microphone Function; Support Bluetooth Function, Bluetooth Version 5.0; Description: 1. Type: MP3 Decoder Board;Power:2 x 5W(Connected Microphone Function) 2. Model: JQ-D129BT-A 3. Function: Bluetooth Decoder 4. Material: Shell Material: ABS; PCB Board Material: FR4 Detailed Keystrokes Color: As Shown Material: ABS+FR4 Size: about 94x35x38mm Package Contents: 1 x Decoder Board 1 x Remote Control 1 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.