The Cisco MFELX1 100BASE-LX Mini-GBIC SFP Transceiver is an easy-to-install mini Gigabit Interface Converter (mini-GBIC) Small Form-Factor Pluggable (SFP) transceiver module that provides a simple way to add 100BASE-LX capability to your Cisco switch. The module operates at a wavelength of 1310 nm and supports single-mode fiber optic cabling. In a typical operating environment, it can achieve distances up to 10 km, depending on the total attenuation in the fiber plant.