Box comes with TWO MCAB1001 units, each with power adapters and short coax cable.
Essentially, this kit allows you to create a link/bridge on your ethernet network using the coax cabling in your home. This can be useful when WiFi signal is not travelling through the house properly, or you need a more reliable signal for streaming something like video. This can also be used for your XBox, PlayStation, Blu-ray players, Apple TVs, etc. I do have the original packaging.
Please see: http://www.ncix.com/products/?sku=38878 for a more complete description.