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: 5.5 x 2.1 mm Female Barrel Jack (center positive), USB Micro-B Male
Connector A: USB Type Micro-B Male
Connector B: 5.5 x 2.1 mm Female Barrel Jack
Connection Split/Duplication: 1:1
Output Voltage: 5 V