Cool smartphone speaker box design, the “Smart Horn” was produced by Hayakawa-san, no batteries required! http://bit.ly/1aQjWge
The Smart Horn does not require electricity, you can use it anytime, anywhere. It is good as the interior is decorated clearly where you place because there is no need to worry about the wiring. Sharpener thin wood, it is amplified as it is the sound of the built-in speaker of the smartphone to the structure to resonate the sound effectively.