“Nomen est omen”

JACK the GRIPPER with the dimension 140/80-18 he is no less than his name and offers a bloody lot of grip. A more stable sidewall provides first-class lateral guidance. The No-Bounce rubber compound allows maximum GRIP in streambed and on wet stones.
The arrangement of the knobs in V-shape and with a height of 14.3 mm ensures extreme forward propulsion in boulders and deep ground.

Of course, it is available in four different hardness/rubber compounds:

HARD, MEDIUM, MEDIUM+ and SOFT.