Shaft stiffener

How stiff or soft a boot should be is a matter of taste. Dressage rider often request a stiffener on the outside of the boots, jumper prefer soft boots which offer a maximum of mobility.
The stiffness of a boot depends on what kind of upper-leather and the lining we use and on what kind of stiffener we attach to the boots.
We differentiate between a medium stiffness, called upper leather stiffener and a very hard stiffener, the Sir-stiffener.