100% Cisco Compatible. Guaranteed. The GLCSXMMDST is a Cisco GLC-SX-MMD compatible fiber transceiver module that has been designed, programmed and tested to work with Cisco brand compatible switches and routers. It delivers dependable 1 GbE connectivity over fiber cable, for 1000BASE-SX compliant networks, with a maximum distance of up to 550 m (1804 ft). This SFP module is hot-swappable making upgrades and replacements seamless by minimizing network disruptions. All StarTech.com SFP and SFP plus transceiver modules are backed by a lifetime Manufacturer's warranty and free lifetime Manufacturer's multilingual technical support. StarTech.com offers a wide variety of SFP modules and direct-attach SFP Cables, providing the dependability and reliability you need to ensure consistent network performance.