Here are the data... That rail is 22 years old, at first the funbox was made of wood except for the rail, then I replaced everything with a metal structure and added another rail, same size and length with the difference that in the upper part It has round tubes, the idea was that they learn using square rail and once they are confident they learn to use round rail later. That type of funbox is the smallest that I built, then all the others are round rail and bigger and bigger, so you change the funbox as you learn, it is to increase the level of difficulty and with the idea of ​​giving them experience and trust, by the time they go to other places and see high, round rails they already know how to approach them.