No. 7 Radio Control Tower is standard production. The No.6 is a factory prototype. I found this prototype tower at york in 1998. The artwork is so good that several astute Marx collectors had picked it up and put it back down. I have to admit, I had it in my hands in the spring and put it down because the dealer was so slow. Fortunately, I was more patient in the fall and it was then, while waiting again, that I realized that it was hand painted! When I got it home and looked more closely I realized it was completely hand fabricated! It is hard to imagine that the Marx artists could paint that well.