Storage unit configured for the storage of objects, comprising a containment structure provided with at least one opening that communicates with the external environment, wherein said containment structure houses the following: - an accumulation structure suited to accumulate a plurality of said objects, comprising a plurality of vertical walls spaced from and facing each other and aligned one after the other along a first horizontal direction that is orthogonal to said vertical walls; - a plurality of guide means present on at least one of the surfaces delimiting each one of said vertical walls and configured so as to define second horizontal directions parallel to one another and orthogonal to said first horizontal direction, said guide means comprising a plurality of recesses and a plurality of alternating projections arranged one after the other and developing along said second horizontal directions in such a way as to give a lined appearance to each one of said surfaces of said vertical wall; - a plurality of trays, in each one of which it is possible to identify: - at least one shaped housing comprising a shaped cavity provided in said tray starting from its upper surface, said shaped cavity being configured to accommodate at least one of said objects; - shaped edges parallel to each other, arranged on opposite sides of said tray and each comprising at least one projecting tab, configured so that they can be slidingly coupled in said guide means when said tray is inserted between any two of said consecutive vertical walls; - moving means suited to move said trays with said objects, said moving means being configured so as to access said accumulation structure and said opening and to insert/extract said trays in/from said guide means, characterized in that it comprises spacer elements suited to be superimposed to one another and to the upper surface of said tray and connection means suited to removably connect said spacer elements to one another and to said upper surface to vary the depth of said shaped housing of each one of said trays, wherein - the measurements of the height of each one of said spacer elements and of the length of said recesses are correlated with each other according to the relation H = L; - all of said recesses have the same length and the same pitch, and all of said projections have the same thickness which is equal to the thickness (S') of said projecting tabs, said length, said height, said pitch and said thicknesses (S, S') being measured along said vertical direction parallel to said vertical walls and orthogonal to said second horizontal directions (X, Y). - an accumulation structure suited to accumulate a plurality of said objects, comprising a plurality of vertical walls spaced from and facing each other and aligned one after the other along a first horizontal direction that is orthogonal to said vertical walls; - a plurality of guide means present on at least one of the surfaces delimiting each one of said vertical walls and configured so as to define second horizontal directions parallel to one another and orthogonal to said first horizontal direction, said guide means comprising a plurality of recesses and a plurality of alternating projections arranged one after the other and developing along said second horizontal directions in such a way as to give a lined appearance to each one of said surfaces of said vertical wall; - a plurality of trays, in each one of which it is possible to identify: - at least one shaped housing comprising a shaped cavity provided in said tray starting from its upper surface, said shaped cavity being configured to accommodate at least one of said objects; - shaped edges parallel to each other, arranged on opposite sides of said tray and each comprising at least one projecting tab, configured so that they can be slidingly coupled in said guide means when said tray is inserted between any two of said consecutive vertical walls; - at least one shaped housing comprising a shaped cavity provided in said tray starting from its upper surface, said shaped cavity being configured to accommodate at least one of said objects; - shaped edges parallel to each other, arranged on opposite sides of said tray and each comprising at least one projecting tab, configured so that they can be slidingly coupled in said guide means when said tray is inserted between any two of said consecutive vertical walls; - moving means suited to move said trays with said objects, said moving means being configured so as to access said accumulation structure and said opening and to insert/extract said trays in/from said guide means, - the measurements of the height of each one of said spacer elements and of the length of said recesses are correlated with each other according to the relation H = L; - all of said recesses have the same length and the same pitch, and all of said projections have the same thickness which is equal to the thickness (S') of said projecting tabs,