USB 3.0 is a or specification rather than a single physical "piece" . It defines the protocols and electrical requirements for "SuperSpeed" data transfers, reaching theoretical speeds up to 5 Gbps窶排oughly ten times faster than USB 2.0.
While it's a standard, you will encounter it in specific hardware "pieces" such as:
The internal chip on a motherboard that manages the USB 3.0 interface. Technical Quick Facts: Usb 3.0 Motherboard Adapter - Amazon.com