Specifications:Operating voltage: 2.5V-5.5VMaximum output power: 3W*2(5V 4Ω)Length: 29mmWidth: 20mmOverall 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:3 x PAM8403 Audio Amplifier Module