Charge two devices at the same time with the AT&T Cube Dual USB 2.1A + 1A Charger. Equipped with two USB ports, the Cube lets you charge two devices at the same time. And with a combined output of 3.1A, the Cube can charge a tablet and a smartphone at the same time and charge them quickly. The Cube is compatible with USB-chargeable cell phones, smartphones, tablets and media players.