Blades are adjusted by pulling on spring loaded detent pin, simultaneously rotating the blade (by hand) into another hole in a locating tab then releasing the detent pin to lock in the new position. Alternatively, an in-car adjuster kit can be fitted to adjust on the move.
When both blades are in the fully stiff position, rotating one blade to the fully soft position reduces the linear rate of the bar by approx. 40%. Then rotating the other blade to the soft position reduces the bar by a further 40%. This large range of adjustment is incredibly useful to set up the overall roll stiffness of the car to suit the spring rate, tyres and driver preference as well as balancing the relative front-to-rear stiffness for grip balance (typically over/understeer).