The rack 10 is designed to be lifted by a forklift or other lifting machine having a fork (e.g., a stacker or a pallet jack). To that end, as shown in FIGS. 2 and 3, in this embodiment, the base 22 defines two openings 50, extending from the front wall 65 of the base 22 on the front side of the rack 10 to the rear wall 65 of the base 22 on the rear side of the rack 10, for receiving a fork of the lifting machine along the depth direction. More specifically, each opening 50 can receive a respective arm of the fork of the lifting machine. As shown in FIG. 2, in this embodiment, the rack 10 also defines two openings 30 extending in the lateral direction, from one lateral end of the base 22 to the opposite lateral end of the base 22, for receiving a fork of the lifting machine along the lateral direction. In other embodiments, the openings 30 may be omitted.

As will be described below, a plurality of attachment members 1100, 1200 are provided to position the rack 10 between two of the vertical support units 104, namely a left vertical support unit 104 and a right vertical support unit 104, and to connect the rack 10 thereto. In particular, in this embodiment, two front attachment members 1100, 1200 and two rear attachment members 1100, 1200 are provided, namely front left and front right attachment members 1100, 1200 and rear left and rear right attachment members 1100, 1200.