I was watching the Montenego ?? brothers show from Dallas and one of the contractors had a tool that showed the difference in height from room to room.
Main instrument was sat at high point and connected probe was taken to each room. Does any one know what the name or brand of this tool is, I have tried a generic google search and cant find it. Thanks

I have seen this tool used by some builders in the past. Like you I do not remember the name of it. It uses a barometric reading device to tell you the height of each area you set it at. Its connected to a small wire that is pulled around from room to room in which it sends readings back to the main station.
Works in the same method as a transit.

I do know its very expensive and unless you need someting like this for perhaps designing a home its not worth the money you will pay. Its also very fragile, and unless your the only one using this you expect that it will be broken by the first person that did not pay for it.

If I dig up the information I will re-post it.