The Sound flow Soundboard SP40 is the perfect speaker. It use sound flow technology to enhance the sound that comes from you smartphone. Just simply place the phone on the sound board and play the music. The Soundboard also comes with a 5000mAh rechargeable battery that lets you charge your phone while you play music. This large capacity battery can charge you phone to full twice (depending on phone battery). It also has a LED battery gauge that lets you know what the battery level of your soundboard is. This way you will never run out of battery.