The SFP-10G-BX-U-20-ST is a Cisco SFP-10G-BX-D-40 compatible downstream fiber SFP transceiver which pairs with StarTech.com's SFP-10G-BX-U-40-ST. They are designed, programmed and tested to work with 10GBase-BX compatible Cisco switches and routers. The SFP+ transceiver module supports a maximum distance of up to 40 km (24.8 mi) and delivers dependable 10 GbE connectivity over fiber cabling. Technical Specifications: Wavelength: 1330nmTx/1270nmRx Maximum Data Transfer Rate: 10Gbps Type: Single Mode Fiber Connection Type: LC Connector Maximum Transfer Distance: 40 km (24.8 mi) Power Consumption: < 1.6W DDM: Yes This SFP+ fiber module is hot-swappable, making upgrades and replacements seamless by minimizing network disruptions. StarTech.com SFPs All StarTech.com SFP & SFP+ transceiver modules are backed by a lifetime warranty and free lifetime multilingual technical support. 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.