What aspect of the major axis is important for carabiner safety?

The major axis of a carabiner is critical for safety because it is designed to support the maximum load capacity during use. When a load is applied to the carabiner, the major axis is the strongest orientation, allowing it to bear the weight without risk of failure. This orientation maximizes the strength of the carabiner and ensures that it can handle heavy loads safely, which is vital in rescue situations or when climbing.

The other aspects mentioned, while they may contribute to the overall usability of the carabiner, do not specifically address its ability to reliably support weight. Flexibility, ease of clipping, and durability are beneficial features but do not directly relate to the crucial function of supporting maximum loads.