Interesting looking piece.labor and cost intensive as well ,450-500 snowmobile studs are $400.alone not including the time to drill and tap the holes in that roller.no visable power source and the closest wheel is adjustable and the spiked one is tensionable.I really do not know the answer,my best quess is that it is used to turn a road racing slick into a damp track tire during a pit stop.But really I dont know...