JBL Free is designed with busy, on-the-go, consumers in mind. The innovative charging case is an integral element in providing a superior user experience, as it not only acts as a docking station for the earpieces, it is also an enclosure for 1500mAh back-up battery, providing a combined 24 hours of use. After extensive research on user behavior, the Harman team achieved a design with smooth curves and symmetric balance that fits naturally, invisibly, in the ear. This is unlike many of its competitors, whose products protrude visibly.