Which type of deformation allows the use of a 5mm spacer at the corner fitting for measurement?

The correct answer indicates that top side rail outward deformation is the type of deformation that allows for the use of a 5mm spacer at the corner fitting for measurement. This specific deformation refers to the bowing or bending of the top side rail away from the container's interior, which affects how the corner fittings align.

When the top side rail deforms outward, it can create a scenario where the fittings at the corners may be misaligned or require adjustments for accurate measurements. A 5mm spacer can be used effectively in these instances to compensate for the distance created by the outward bending. This allows for achieving proper fitment or measurement without compromising the structural integrity of the container.

In contrast, other types of deformation may not facilitate the same use of a spacer. For instance, upward deformation could raise the corner fittings but wouldn't necessarily require spacing adjustments to maintain measurements. Similarly, rear sill outward deformation or bottom side rail inward deformation might result in different alignment issues or measurements that don't align with the conditions specified for utilizing a 5mm spacer. Thus, the unique characteristics of outward deformation at the top side rail makes it particularly significant for this measurement context.