Features: 1. PAM8403 mini type D digital power amplifier can be easily put in small space of many digital products, high amplification efficiency. 2. It can be powered by computer USB 5V, or phone charger 5V, or lithium battery. 3. High efficiency 90%, can provide 3W (left channel)+3W (right channel) when using 4Ω load and 5V power supply. 4. Type D power amplifier has very high amplification efficiency, sound quality will not be effected by temperature rise, no need of heat sink. 5. Build-in noise reduction circuit, no noise when power on/off, supports short circuit, over current and over temperature protection. 6. Widely used for LCD TVs, monitors, laptops, portable speakers, DVD players, game players, phones. Specifications: Working Voltage: 2.5V-5.5V DC (should no over 5.5V, pay attention to polarity) Suitable Speaker: 4-8Ω (4Ω is recommended); speaker power 2-8W Size: 2.3×1.8cm/0.9×0.7in Quantity: 5pcs Weight: 2g(approx.) Package Includes: 5 × Power Amplifier