Has written warranty NoTP-Link TL-SM321B-2 1000Base-BX WDM Bi-Directional SFP Module NoTP-Link TL-SM331T | 1000Base-T RJ45 SFP Module | 1.25G Copper SFP Transceiver | SFP to Ethernet | Plug and Play | Hot Pluggable | Up to 100m distance | | Durable Metal Casing | Versatile Comp...