Which item relates directly to ensuring load stability when using clevises?

Ensuring load stability when using clevises is crucial for the safe operation of sling loads. Hand tightening directly contributes to load stability by allowing personnel to secure the clevis attachments firmly by hand, reducing the risk of any movement or slippage during transport. This action ensures that the load remains stable throughout the entire rigging and transport process, minimizing the chance of accidents or mishaps that can arise from improperly secured loads.

Other items listed, while they may be related to various aspects of load management or securing, do not have the same direct impact on ensuring the stability of the load when specifically using clevises. A load bag is typically used for adding weight to stabilize lighter loads but does not itself ensure stability in the context of clevis use. Nut closures are important for fastening but are typically used with fasteners and do not have a direct role in adjusting or securing clevis connections for stability. An apex sensor is designed to monitor load behavior and tension but does not provide direct stabilization through physical contact and securing like hand tightening does.