What might be used in addition to cribbing when the opening is too large?

When an opening is too large, step chocks can be utilized alongside cribbing to provide additional support and stability. Step chocks are designed to fit variably into the configuration of cribbing and can help prevent movement by wedging into the gap created by the opening. This supplemental support is essential, particularly in rescue situations where maintaining the integrity of the structure is critical for safety.

In contrast, while manual cutting tools, pneumatic tools, and chains are valuable in certain extrication scenarios, they do not serve the same purpose as step chocks in stabilizing or supporting structures. Manual cutting tools and pneumatic tools are primarily used for cutting or reshaping materials, which does not address the immediate need for stabilization. Chains, although they can provide a means to secure objects, lack the stability and support characteristics inherent to step chocks and cribbing systems. Therefore, step chocks are the best choice when needing to complement cribbing and ensure a safe environment during extrication operations.