Feature:1. Working voltage is 2.5V-5.5V. The power supply voltage should not exceed 5.5V, and the power supply should not be reversed.2. Speaker 4-8 ohms, 4 ohms recommended. Speaker power 2-8W.3. It can be powered by the computer's USB port 5V power supply, or by using the mobile phone charger USB port 5V power supply, or you can use the lithium battery power supply.4. High efficiency 90%, 4W load and 5V power supply, 3W (left channel) + 3W (right channel) output power. The efficiency of Class A and Class B power amplifiers is only about 30%, and Class D power is highly regarded under the current green trend.5. Class D power amplifiers are extremely efficient, do not affect the sound quality due to temperature rise, and do not need to add heat sinks, occupying a small volume.6. The power amplifier board has a built-in noise canceling circuit. There is no noise when the power is turned on/off. The module has short circuit over current protection and over temperature protection.7. Ultra-miniature design, it can be easily placed in the small internal space of various digital products, and the amplification efficiency is very high.Spezifikations:Application:LCD TV, monitorlaptopPortable speakerPortable DVD player, game consoleMobile/Hand-free phonePackage List:7 * PAM8403