I have been lucky enough to use one of these interesting Treadwalls at my local gym. The workout is great and is a lot more immersive than typical gym equipment. This clever machine is able to change the position of the rocks, the speed and the angle to make it an easier or harder climb. One thing I definitely loved about the Treadwall was that there is no top, and I could climb for as long as my body would allow me.
Go to: www.brewersledge.com/home
for the official Treadwall website.