The QSFP-40G-CSR4-ST is a Cisco QSFP-40G-CSR4 compatible fiber transceiver module that has been designed, programmed and tested to work with Arista Networks brand switches and routers. It delivers dependable 40 GbE connectivity over fiber cable, for 40GBase-SR4 compliant networks, with a maximum distance of up to 400 m (1312 ft.). This QSFP+ fiber module is hot-swappable, making upgrades and replacements seamless by minimizing network disruptions. StarTech.com offers a wide variety of SFP modules and direct-attach SFP cables, providing the convenience and reliability you need to ensure dependable network performance.