Where you position your Access Point will define the limits of your wireless network. For the best coverage, you want your base station mounted high and in a central location. Odds are there’s no electric outlet there.
How do you solve the problem? You use the ethernet cable itself to power the AirPort base station with the MacWireless POE kit. The kit includes 2 adapters. The only additional item you will need is a long-enough cat-5 or cat-5e Ethernet cable to install between the 2 adapters. The kit uses the existing power supply which came with your AirPort base station. The kit makes use of otherwise unused wires in your Ethernet cable and has no effect on data integrity.
MacWireless Power Over Ethernet (POE) allows mounting your AirPort base station where there may be no electric power outlet, up to 250 feet away for AirPort snow (Dual-Ethernet) & 150 feet away for AirPort graphite (Single-Ethernet). A pair of adapters carry the DC power in the data cable.
This product does not work with Airport Extreme. MacWireless are currently designing an Airport Extreme version.
For US$29.98, it’s an inexpensive way to power Base Stations in places far away from electric outlets. More info here.