Figure 8 (climbing)

This device utilizes a large surface area in contact with a climbing rope to provide sufficient friction along with the proper technique to be used as a belay device or for rappelling.

Figure-eights offer a smooth controlled descent when rappelling and lowering climbers.

[1] 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.

The figure-eight cannot be removed from the rope without detaching the device from the harness, and so could be accidentally dropped, particularly when tackling a rebelay.

They do not provide a convenient means to temporarily lock the descent at a rebelay.