The Atlona USB to 5V DC Locking Power Cable powers select 5V DC Atlona devices off of a USB outlet, the kind available on a computer, cable box, or USB hub, for some examples. You'll be able to make use of USB power when no wall outlet is around, or simply for convenience. The cable is 6 ft long and has a DC connector on one end and two USB connectors on the other. If your 5V device works on 2.5W of power or less, you can use just one USB connector; if 2.6 - 5W, then you'll need to plug both in. You can plug both in regardless, if only just to be safe, and you won't experience any drawbacks if the second one is unnecessary.
The DC end features a push-in locking component that snap-locks into compatible Atlona devices. Accordingly, this cable may not work with a non-Atlona device as the locking component could interfere with securely connecting into the device. Compatible Atlona devices include 5V switchers and extenders.