Charge your 5V DC devices through a USB port on your computer - Tired of having to carry around a separate wall adapter in order to power or charge your 5V devices, such as certain external hard drives, streaming media players, and Bluetooth speakers? This USB power cable makes it easier to power 5V DC devices that have a (OD: 5.5mm, ID:2.1mm) barrel power connector. Length: 30cm only; You can power or charge the devices through an available USB port on your laptop or desktop computer. Expertly designed and constructed of high-quality materials,