With this rubber band over the top wheel of an English wheel, you can shape (fold) metal instead of stretching it. The rubber band will cushion the curve from front to back.
Ideal for panels with a slight curvature or for e.g. a drive shaft tunnel where you want a rounding in the metal, but want the panel flat from front to back. The softer wheel only creates a curve from left to right (according to the rounding of the lower wheel). The panel that is formed remains straight in the travel direction. The rubber band helps to form metal faster and with more control.