Much smaller than expected and very good for small audio applications where size matters / performance / value!

The modules are really tiny. My calipers says 24 x 15.75 x 3.8 mm. Let good about the 5V from the USB phone charger or battery operated and are amazingly well! The audio quality suffers in no case less than the size! Heavy is designed only rewire because the cables are really tiny need to fit in the terminals and solder designed also more than awkward in the order), it is feasible, however, and for the money you get nothing better.

For those seeking a booster for bathroom Radio, mobile phone speaker, kitchen radio or model this is perfect here. Of course, 3W are not much, but for speakers over 85dB / W the things go quite neatly from;)

Strong buy recommendation!

PS: On Youtube there are several videos that show how well these modules are able.

In Addition:
In a HiFi Forum even a Mobile Disco Box was built with modules like power class (one probably it was even this one!) The whole had speakers with over 100dB / W and was operated by the battery was again charged by a small solar panel. Due to the low consumption so is a box created the permanent can run at full volume without the battery is empty;) damn loud part is also .... Genial!