Box with base resistant to opening and having its portions breakable to prevent it from being reclosed after its initial opening

A box which has an opening-resistant base with break-off portions and is formed from a single piece of cardboard, it comprising four lateral walls, at least one lid or base projecting from an end of one of said lateral walls, two flaps each projecting from the end of a respective lateral wall adjacent to that from which said base projects, said base consisting of a panel projecting directly from the lateral wall of the box and a tab projecting from the free end of said panel, the panel being separated from the respective lateral wall and from the tab by parallel folding lines, said flaps also being separated from the respective lateral walls by folding lines and each having a hook-shaped tooth provided in proximity to the free end of the flap on that side thereof opposite the box base panel, the length of the two flaps being such that when they are folded one towards the other in the box when closed, the hook-shaped tooth of one flap becomes superposed on the hook-shaped tooth of the other flap, there being provided in the box base tab, in proximity of the folding line which separates it from the panel from which it projects, a cut through which the hook-shaped teeth projecting from the two flaps on which the base panel is superposed in the box when closed are positioned and extend, wherein a breakable knurling extends from each end of said cut as far as the adjacent lateral edge of the base panel.