MaiTech 03100547 Mini USB Powered 3W Digital Amplifier Board - Deep Blue
L+ L- and R+ R- connect to speaker; GND connect to power negative part; +5V connects to power positive part; Audio input connects to L-IN R-IN GND; Power: DC 2.5~5.5V; Output power: 3W + 3W; SNR: 90dB; Size: 19 x 20mm; Installing hole: 2.8mm; Thickness: 2.8mm; Voltage can not beyond 5.5V; Built-in gain buffer; Input cable better be shielding cable; Output is BTL driving mode; Cables of speaker are independent.