Features: Operating voltage: 2.5V-5.5V Maximum output power: 3W*2(5V 4) PCB size : Length: 29mm Width: 20mm Overall height after installed is about 16mm. Note: please make sure the power supply is not more than 5.5V and please don't do reverse polarity for "+" and "-" or else it will burn the board. Package Included: 1xPAM8403 3Wx2 5V Dual Channel Power Audio Amplifier Board