Figure 8 (belay device)
The figure 8 belay device is a piece of metal (usually an aluminum alloy) in the shape of an 8 with one large end and one small end. This device utilities a large surface area in contact with a climbing rope to provide sufficient friction along with proper technique to be used as a belay device or for rappelling. A figure 8 (sometimes just referred to as an 8) is used in conjunction with a climbing harness and locking carabiner to keep a climber safe and control their descent or one's own descent (when rappelling)
Figure 8s offer a very smooth controlled descent when rappelling and lowering climbers. They can be used with nearly any diameter climbing rope and don't get as hot as other friction devices because of their ability to dissipate heat efficiently.
- Cox, Steven M. and Kris Fulsaas, ed., ed. (2003–09). Mountaineering: The Freedom of the Hills (7 ed.). Seattle: The Mountaineers. ISBN 0-89886-828-9.