What is a load retainer commonly made from?

The correct answer is that a load retainer is commonly made from a section of "L" angle steel. Load retainers are structural components used in intermodal shipping containers to help secure cargo in place, preventing it from shifting during transport.

Using "L" angle steel provides the necessary strength and durability required to withstand the forces exerted by the cargo, especially in transit where movement can be substantial. The shape of the "L" angle allows for easy attachment to container walls, adding stability without requiring excessive space.

Other materials like flexible plastics, composite wood, or lightweight aluminum alloys may not provide the same level of structural integrity and stability needed for load retention in demanding shipping environments. Consequently, while these materials might be suitable for other applications in shipping or container design, they are not commonly used for load retainers due to their potential limitations in strength and resistance to heavy loads.