Arnold, It uses a wifi system to broadcast directly from the camera in the cupola of the caboose to a smart phone, tablet or computer signed into the cabooses wifi.
The neatest part is that it supports as many units as want to sign on to watch, so an entire group can get a birdseye view without crowding the layout. The program is free to download to smart phones and tablets, and the included disc uploads the program to any computer.
You can turn it so looking behind the train to see where you have been, or turn it to watch over the top of the train, or you can put it in front of an engine and watch where going, it allows making videos as well.
It is anywhere from low $90's at some retailers to $130 on Ebay.
