Protective Function - Over-voltage Protection, Under-voltage Protection, Over-heat Protection, Short-circuit Protection, This means that the Bluetooth amplifier board is not easily damaged.Extremely low noise, quality, extremely low distortion, protecting your for original-sound experience.Transparent sound, fast low-frequency response, strong mid frequency texture, high frequency smoothness, and minimal loss.Thickened heat sink, silent and long-life fan; Solved the heat dissipation problem and better utilized the advantages of high power.Multiple audio input methods - The amplifier offers multiple input methods, including Bluetooth, AUX, USB flash drive, and USB sound card input. This versatility allows you to connect it to audio sources such as smartphones, computers, MP3 players, and more, ensuring compatibility with your preferred devices.Model:-301BName:Mono 30W Bluetooth audio amplifier modulePower amplifier chip:domestic chipBluetooth version:5.3Bluetooth transmission distance:15 metersAudio input:Bluetooth +AUX+U disk +USB sound card Audio output Mono:30WPower supply:DC9-24V, 3A (no AC)Adaptive horn:4-8Ohm, 5-30WColour:BlackMaterial:PCBPackage Contents:1 * Audio Amplifier Board1 * ScrewdriverOnly 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.