Feature:- Support reading MP3 songs in TF-card / U-disk.- Independent adjustment of Treble, Bass and Master volume.- Built-in Bluetooth Receiver and FM Radio Function.- With AUX input port, can be connected to the PC/Phone/CD.- Dual microphone input, adjustable reverb.- Support Voltage AC 110V/ 220V or DC 12V/ 24V.How to Connect Bluetooth ?1. Press "MODE" button to switch it to Bluetooth status.2. Open phone Bluetooth, search the Bluetooth device and connect.3. You can use it after pairing successfully.Description:Type: Bluetooth Amplifier BoardModel: D10Bluetooth Version: 5.0Audio Channel: 1.0Rated impedance: 4Rated Power: 40WPower Range: 30-120W (Deponds on Voltage)Distortion: 0.03%S/N Rate: 92dbBattery of Remote: CR2025 x1(Not Included!)Feature: FM Radio / Treble / BassVoltage: AC 110/220V, DC 12V/24VInput: Bluetooth/3.5mm RCA/U-Disk/TF/MICHow to use Radio ?1. Hang up the Radio Antenna.2. Press ''MODE'' button to switch it to the radio state.3. Press the ''Play'' button to search the entire channel and save.4. Press the previous / next track to switch to use.TIPS: This is not professional radio, no good effect, pls understand!TIPS:1. Support AC 110V / 220V, automatic adaptation.2. If connect to DC 12V-24V, the Current needs more than 3A.Warning: Pls select only one connection method !!!To match the AMP and Speaker:1. The impedance of the amplifier is the same as the speaker, can not be too far apart.2. The power of the amplifier is 1.5 times than speaker to obtain a enough sense of strength.=> If the output impedance of the amplifier requires 4-8, the impedance of your speaker should also be 4~8, the sound of 4 ohms is louder, and the 8 ohms is smaller;=> If the output power of amplifier is 35W, the speaker should be around 20W. For 1.0 channel, the power is 20-30W, for 2.0 channel, it is 2x(20-30)W.=> If the amplifier is full frequency, the wider the frequency response of the speaker, the better, such as 100~18KHz.TIPS: The speakers must be based on impedance and power, regardless of dimensions. If the sound is intermittent or hoarse during increasing the volume, it means the speaker and amplifier are not matched, Pls use small sound or change a suitable speaker. Pls make sure that the required power supply is used and working properly.