This is a 125M to 4G OEO converter (3R Repeater) with 2 open SFP slots. The open SFP port allows users to customize between the SX, LX, or BX connections. This provides a connection between fiber to fiber 10Gbps ethernet equipment, and functions as a fiber mode converter, or as a fiber repeater for long distance transmission. This can be used in telecommunication rooms, R&D laboratory, data center, or other network uses. This device can be managed if used in our managed rack system or unmanaged with our unmanaged rack system or standalone chassis enclosure. The media converters and network interface cards are 100% compliant for all of the networking needs. Now you have a cost effective solution to your network upgrade needs.