The QSFP-40G-ESR4-ST is an MSA compatible fiber transceiver module that has been designed, programmed & tested to work with MSA brand switches & routers. It delivers dependable 40 Gb E connectivity over fiber cable, for 40 G Base-SR4 compliant networks, with a maximum distance of up to 300 m (984 ft). This QSFP+ fiber module is hot-swappable, making upgrades & replacements seamless by minimizing network disruptions. Star Tech.com offers a wide variety of QSFP+ modules & direct-attach QSFP+ cables, providing the convenience & reliability you need to ensure dependable network performance.