X2 is a standardized form factor for 10 Gb/s fiber optics transponders. Both 10G Ethernet and 10G Fibre Channel versions are available. X2 transponders are used in datacom optical links only (not telecom). XFP is a standardized form factor for serial 10 Gb/s fiber optic transceivers. It is protocol-independent and fully compliant to 10G Ethernet, 10G Fibre Channel, SONET OC-192 and SDH STM-64. XFP transceivers are used in datacom and telecom optical links and their benefits are a smaller footprint than other 10 Gb/s transponders (such as XENPAK, X2, XPAK AND 300-PIN). XPAK is a standardized form factor for 10 Gb/s fiber optics transponders. Both 10G Ethernet and 10G Fibre Channel versions are available. XPAK transponders are used in datacom optical links only (not telecom), and their main benefit is a smaller size than other 10G transponder form factors like XENPAK and X2.