The Killer E3000 25 Gigabit Ethernet Controller is a high-performance network interface controller (NIC) designed for gamers, streamers, and professionals who require ultra-fast and stable network connections. It supports 25 Gbps Ethernet speeds and is typically found in high-end gaming PCs or workstations. The Windows driver for this controller allows your operating system to properly communicate with the hardware, enabling it to take full advantage of the high-speed network capabilities.