10-Gigabit Ethernet XENPAK transceiver is a hot-swappable I/O devices that plug into 10-Gigabit Ethernet module ports. The XENPAK transceiver is available in either optical or copper interfaces. It is used in typical router line card applications, storage, IP network and LAN. 10-Gigabit Ethernet X2 transceiver is a standardized form factor for 10 Gb/s fiber optic transceivers that is used for data transfer rates from 10.3 Gb/s to 10.5 Gb/s. X2 transceiver is used in datacom optical links only (not telecom), and they are smaller than old generation XENPAK transceiver. Its electrical interface to the host board is also standardized and is called XAUI (4 x 3.125 Gb/s).