Function usage: 1. Bluetooth function: After powering on, the power amplifier board say Bluetooth mode when it is turned on. At this time, go to the general settings of the phone - Bluetooth - turn on - connect the signal HT-1688AT. If the signal is successfully connected, you can use Bluetooth! 2. Memory card/U disk: If you have a memory card, the U disk be automatically recognized when plugged into the amplifier board! 3. Audio mode: If you use an audio cable to connect to the power amplifier board, turn on the computer and the Mode button on the remote control to switch to the audio mode (the mode she read as the audio source input is the audio cable), plug in the audio cable and you can use it. Support reading MP3 songs in TF card and U disk. Support adjustment of treble, bass and master volume. Dual microphone input, adjustable reverb, built-in Bluetooth and FM radio. Voltage: 220V DC: 12-24V Note: The amplifier board is powered after it is powered on. This green circuit board cannot be touched. It is recommended to plug in the speaker wire before assembly, install it on the speaker box, and then turn on the power. Plug Type: EU Plug, it applies to Indonesia, Germany, France, Spain, Italy and so on. Panel: 13.8 x 8.5cm Green function board: 10 x 5.2cm Material: iron colour: As shown Package Contents: 1 x speaker cable 1 x remote control 1 x 12VDC cable 1 x 220v European power 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.