"When working or performing a rescue from height access from above allows users to take full advantage of gravity"
PPE Descending devices have been designed to accurately regulate the friction of the device itself on the rope which it has been installed upon. The braking mechanism usually consists of a pivoting cam, pinching the rope under the weight of the user. The cam is releasable by means of a handle, thus facilitating descent.
Descenders allow users to position themselves at any point on the rope. Descenders such as the Petzl I'd can also be used to safely belay a leading climber.