Which equipment is centrally used in the frog technique for ascension?

The chest ascender is a critical piece of equipment utilized in the frog technique for ascension. This technique is specifically designed to allow a rescuer to ascend a rope efficiently and effectively while maintaining a stable position. The chest ascender, usually worn on the chest, helps in securely climbing the rope while keeping the body aligned.

When using this technique, the chest ascender operates in conjunction with a sit harness, allowing the user to ascend while using their legs for powerful movements and their upper body to remain balanced. This combination enables climbers to rapidly progress along the rope while minimizing fatigue, making it advantageous in rescue operations where time and efficiency are crucial.

In contrast, the other options serve different purposes. A static rope is foundational to the technique but does not facilitate movement by itself. A climbing helmet is essential for safety but does not contribute to the actual ascension process. Similarly, while a firefighter harness is important for fall protection, it is not the primary device used for the specific ascension method described in the frog technique.