The Cisco GLC-SX-MM is a 1 Gigabit (1Gbps) Small Form-Factor Pluggable (SFP) transceiver module for short-reach fiber connections, supporting the 1000BASE-SX standard over multi-mode fiber (MMF) up to 550 meters, using an 850nm wavelength and LC connector, ideal for linking Cisco switches/routers for flexible, hot-swappable network expansion.