The 75 cm Rasierschnitt Blade is for more expansive areas like the 75cm Black blade, but is more suitable for fibrous and varied vegetation. It is stronger than the black blade due to more curvature in cross section. (It is the flatness of the black blade that allows it to mow closer to the ground in greener grass, but makes it more fragile.)
It can mow more stalky stems, like smaller thistles and weeds, but not "woody" stems like the bush blade.
RABL75