Cisco SFP-10G-BX-U-20 Compatible Transceiver - 10GBASE-BX WDM SFP+ (10 Gbps) - 10 Gigabit BiDi Module - 1270nmTx/1330nmRx Single Mode Fiber (SMF) - 20km (12.4mi) - LC Connector & DDM - Hot-Swappable / MSA Compliant - Lifetime Warranty