TP-Link TL-SM321A-2 1000Base-BX WDM Bi-Directional SFP Module | Adopts the latest standard 1000Base-BX | Up to 2 km transmission distance in 9/125 μm SMF (Single-Mode Fiber) | Compatible with Small Form Pluggable Multi-Source Agreement (SFP-MSA) | Supports Digital Diagnostic Monitoring (DDM) | Supports Hot Swappable | 3 Year Warranty