A utility module comprising a base portion and a top portion and having a front side and a back side with a locking path extending between the front side and the back side. The top portion is configured at a back portion thereof with at least one back locking bar and at a front portion thereof with at least one front locking bar extending parallel to said back locking bar. The back locking bar and the front locking bar are disposed parallel to a top surface of the top portion and are spaced from the top surface. The base of the utility module is configured at a back portion thereof with a back bar coupling recess facing towards the back side and having a back under-bar arresting surface and a front bar locking arrangement comprising a front facing barrier wall and a locking lever comprising an arresting tongue extendable in front of said barrier wall and having a front under-bar arresting surface. The locking lever is displaceable between a locked position at which the front under-bar arresting surface extends at a front locking bar arresting space in front of the barrier wall, and an open position at which the locking lever is displaced to facilitate passage of a front locking bar into and from the front locking bar arresting space.