The Hanwag Yukon Wide is a classic trekking boot with leather lining and a comfortable trekking last. The stiffness of the sole, the drop (how rounded the sole is to allow for good rolling), and the shaft construction determine how a model is positioned within the categories. For this reason, you will find the categories A-B-C-D for each model. This gives you an idea of how stiff the shoe is. D = very stiff and fully crampon-compatible. C = stiff and conditionally crampon-compatible. B = firm support and solid, but flexible sole for trekking and hiking. A = soft, very well-flexing construction. Category B/C: The shoe is suitable for demanding hikes in hilly terrain, even on poor paths. Vibram Fuora: Durable trekking sole with medium stiffness and braking lugs.