This reinforcement of the rear portion of the boot is not visible from outside,but its contribution can be felt.  It is made using a seamless 3d plastic inset that improves durability and provides support.  It is shaped for optimum flex and the reduction of pressure points.

US MEN88.599.51010.51111.51213
EU4040.641.34242.643.34444.645.346.6
MONDO260265270275280285290295300310
Union black