This USB 3.0 Y-cable  made for additional power supply of USB devices. Just plug the 2 connectors into 2 free USB ports of your system and the device to the USB female jack of the adapter. Thus your device will be supplied by 2 power sources. The short connector indicates the extra power source and will be provided parallel to the black data/power interface.
 

Specification

• USB 3.0 specification and up tp 5Gbps

• Interfaces: 1x USB A female data/power

                      1x USB A male data/power (long cable end)

                      1x USB A male power (short cable end)

• Cable length: 60 cm including connectors

System requirement

• PC or notebook with two free USB ports