This is a Homeplug AV 200Mbps network adapter. Logitech model LA700e. The adapter provides power to your POE (power over ethernet) 802.3af compliant devices (7W max load). Just to be clear, this device supports both ethernet over power (also known as Homeplug or Powerline) and it also supports power over Ethernet (802.3af POE).
Additionally, the device is weather resistant when wall-mounted vertically and with the use of a flat cat5 or cat6 Ethernet cable. If you just do a search for flat cat5 you will find several cables in any length you may need. If you don't care about weather resistance, a plain round Ethernet cable will work although the door will not install unless a flat cable is used. Used indoors, the adapter works fine without the door installed. The adapter allows you to leverage the existing electrical wiring in your home to install an Ethernet port anywhere you have a power outlet.
Logitech sells these adapter in their parts store for only $10 each with free shipping on any order over $20. P/N 993-000495
These adapters originally ship with a Logitech Alert outdoor security camera and so they could certainly be used with any Logitech alert camera. However, since the device conforms to the 802.3af standard, it also can be used with many various PoE devices like IP Cameras, VoIP phones, Wireless Access Points, etc.
For anyone not familiar with homeplug technology, I should mention that you will need a minimum of 2 Homeplug AV adapters on your network. One adapter will bridge your switch/router to your electrical wiring. Each additional adapter can then be used to add a 200Mbps ethernet port wherever you may need one. For homes and offices with multiple breaker panels, the Homeplug adapters do need to be on the same panel.
These adapters may or may not be compatible with other brands of Homeplug AV adapters. I am currently using 10 of these adapters in my house and they work great.
If you search eBay for homeplug PoE, you will find there are very few devices on the market which support both Homeplug AV and PoE. A company called "Level One" makes one called the "PLI-3110" which sells for around $150 for just one adapter and theirs is not weather resistant.
I'm fairly certain the price is an error but it has been this way for a long time. I have purchased several of these and recommended them to friends who have also purchased large quantities. I have all I need now so get them while you can!