Presently there are in use ski boots constituted by a shell to which there is downwardly connected a sole, having a tip and a heel connectable to predisposed bindings fixed to a ski; the shell, usually provided in rigid or semi-rigid plastic material, covers approximately entirely the foot of the user.
To the shell there is rotatably connected, typically at the malleoli area, a cuff, adapted to partially cover the leg of the user to provide a support thereto during skiing.
Internally to the shell and to the cuff there is typically positioned an inner boot, provided in soft material, adapted to increase the comfort-fit for the user.
The main drawback of such known ski boots is that they must be produced, for being adequate to the size of the foot of the user, in various dimensions: this increases production costs, there being necessary different machines and molds for producing the components in the different dimensions, and moreover there exists the problem of stocking the various sizes, for both the producer and for the seller.
As a possible solution to such drawback ski boots are usually produced in a number of limited sizes so as to be able to be used, each one, by users having foot sizes which are slightly different.
This however forces the user to buy a size which does not correspond to the exact dimensions of his own foot, forcing him or her to employ other expedients, such as for example the use of socks of increased thickness, for increasing comfort and for allowing thus to transmit in an optimum manner the forces from the foot to the ski.
Such drawback is greater in the case of users which are children, whose foot typically has dimensions which increase in relatively short times.
Another problem which should be held in mind is the fact that to a fixed size there corresponds a fixed shape of the calf of the user, for which the use of larger sizes and the compensation of the greater space for the foot with a sock may bring about localized areas of compression of the upper end of the cuff on the calf.