This is a pair of 2mm:1ft models of the DX open container as used on British Railways, and they can be used empty or filled with suitable loads, to be carried on model railway wagons such as 'conflat A' types, or my model of the O35 wagon, which was apparently designed for them. These containers could be sheeted, with a tarpaulin resting over the two 'stretchers' placed across the open top. To complete the stretchers for use, separate them from the sprues joining them in fours (you may need spares) clean out the tiny angled holes in their top surface at either end, and the slightly larger central upright hole. Place a short length of wire in the upright hole, and a longer gently curved piece of wire between the angled holes.