Piton

In climbing, a piton (/ˈpiːtɒn/; also called a pin or peg) is a metal spike (usually steel) that is driven into a crack or seam in the rock with a hammer, and which acts as an anchor to protect the climber against the consequences of a fall, or to assist progress in aid climbing. Pitons are equipped with an eye hole or a ring to which a carabiner is attached; the carabiner can then be directly or indirectly attached to a climbing rope.

Pitons were the original form of protection and are still used where there is no alternative. Repeated hammering and extraction of pitons damages the rock, and climbers who subscribe to the clean climbing ethic avoid their use as much as possible. With the popularization of clean climbing in the 1970s, pitons were largely replaced by faster and easier-to-use clean protection, such as nuts and camming devices. Pitons are still found in place (as 'fixed' pitons) on some established free climbing routes in places where nuts or cams do not work; and are used on some hard aid climbs.

Pitons are sized and manufactured to fit a wide range of cracks. From small to large, the most common are:

Wired Chouinard RURP

Knifeblade pitons made by US army during World War II and left in Seneca Rocks

Soft Metal Lost Arrow

Medium size Angle

Medium size Angle in Big Cottonwood Canyon

Z-shaped Angle in Echo Canyon, Utah

Old loose-ring angle piton

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Wikipedia