The PAM8403 Digital Class D Audio Amplifier kit is a small but powerful 5v stereo amplifier that is suitable for MP3 projects. The Amp kit comes with an open-ended USB cable and can be powered by any device that has a USB output, including mobile phone chargers. The 40mm 3 watt speakers allows designers to produce small but effective designs that produces a loud sound quality that will surprise users. The Amp kit comes supplied with a 3.5mm jack cable suitable for most audio outputs including mobile phones. Also included is 15mm switch for those who want to extend their designs further. With easy to follow instructions this kit is simple to construct and small enough to suit a wide range of designs. Click on link below to hear the difference in sound through amplifier and then phone only.