During a descent, what is the main purpose of a descender device?

The main purpose of a descender device is to provide friction and control during a descent. This is crucial for ensuring the safety of the individual descending. A descender manages the rate of descent by applying friction to the rope, allowing the user to slow down, stop, or control their descent as needed. This capability is vital for navigating various terrain and situations safely, preventing uncontrolled falls.

In contrast, increasing speed of descent could lead to dangerous situations, making that choice unsuitable. A descender does not replace climbing harnesses; rather, it complements the harness by working in tandem with it to enhance safety. Additionally, while descenders may be used in conjunction with knot tying in some scenarios, their primary function is not to assist in the knot-tying process. Rather, they are solely focused on controlling the descent itself.