These are the new mini media converters. These are smaller than the HTB-3100, consume less power and heat up less. These have also the advantage of having the RJ45 connector and the fiber optic connector on opposite sides, and the DC connector on the same side of the RJ45 connector. This is much better for the arrangement of the cables, especially when using these devices with a laptop. These media converters are still compatible with the HTB-3100.