TP-Link TL-SM321A-2 1000Base-BX WDM Bidirectional SFP Module LC Bidirectional Optical Interface, Up to 1.25 Gb/s Throughput, Supports 9/125µm Single-Mode Fiber, Up to 1.24-Mile Range, 1550nm Transmit Wavelength, 1310nm Receive Wavelength, Full-Duplex...