The Adaptec AUA-3020 PCI to USB Enhanced Host Controller is a hardware device that provides USB ports to your computer via a PCI (Peripheral Component Interconnect) slot. It's useful if your motherboard doesn't have built-in USB ports or if you need to add more USB ports to your system. This card is particularly used to add support for USB 2.0 (and sometimes older versions of USB) to computers.

The driver for this device ensures that your operating system (such as Windows) can properly communicate with the Adaptec AUA-3020 USB controller, enabling your computer to recognize the USB ports and use them for connecting devices like printers, flash drives, and other USB peripherals.