The Realtek RTL815x USB 3.0 to Gigabit Ethernet Adapter is a small, portable device that allows users to connect to a wired Gigabit Ethernet network through a USB 3.0 port. It is designed for devices such as laptops, ultrabooks, and tablets that do not have a built-in Ethernet port. The adapter uses the USB 3.0 interface to provide a fast and stable network connection with speeds up to 1 Gbps. The Realtek RTL815x chipset is known for its reliability and compatibility with a wide range of devices and operating systems.