Use a 5V power adapter with a barrel connector to power and charge USB devices. This is a great way to create a higher current USB charger using the extra 5V barrel chargers that you have lying around. Connectors: 5.5x2.1mm Female Barrel Jack (center positive), USB Micro-B Male Connector A: USB Type Micro-B Male Connector B: 5.5x2.1mm Female Barrel Jack Connection Split/Duplication: 1:1 Output Voltage: 5 V