The OEM Device Extension driver in Windows is a type of device driver used by manufacturers to provide additional functionality or specific support for hardware components. "OEM" stands for Original Equipment Manufacturer, and these drivers are typically designed by the hardware manufacturer (e.g., Intel, Realtek, AMD, etc.) to support devices that may not be fully supported by generic Windows drivers.

An OEM Device Extension typically includes specialized functions or settings that are unique to a specific hardware device. It can be installed as part of a larger driver package or provided by the hardware manufacturer to ensure compatibility and enhance device performance.

This extension might not refer to a specific, stand-alone device but rather a component that is integrated with other device drivers or used for specific configurations of OEM hardware.