A piton (/ˈpiːtɒn/; also called pin or peg) in big wall climbing and in aid climbing is a metal spike (usually steel) that is driven into a crack or seam in the climbing surface using a climbing hammer, and which acts as an anchor for protecting the climber from falling 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 connected 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 damage 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.^[1] Pitons are still found in place (as "fixed" pitons) on some established free climbing routes, as fixed belay station anchors, in places where nuts or cams do not work; and are used on some hard aid climbs.^[2][3][4]

Pitons are sized and manufactured to fit a wide range of cracks. From small to large, the most common are:^[5]

• RURP (Realized Ultimate Reality Piton) – a tiny piton the size of a postage stamp used in thin, shallow seams. It was designed by Tom Frost and Yvon Chouinard in 1959 and was manufactured by Chouinard Equipment in the 1960s.^[6] It is not a strong piece, and is mainly used for aid climbing, although it can feature as protection on extreme free routes (e.g. Rurp The Wild Berserk (E6 6b) at The Brand, Leicestershire, UK).^[7][5]
• Beak – hooking pitons with the ability to hook, which can be placed without a hammer. Known often as Birdbeaks named for Jim Bridwell whose nickname was "The Bird".^[5]
• Knifeblade – also known as a bugaboos, are thin straight pitons, that work in thin, deep cracks.^[5]
• Lost Arrow – also known as a wedge piton, was designed by John Salathé and Yvon Chouinard (named after Salathé's ascent of Lost Arrow Spire), is a hot-forged, tapered piton for medium-sized cracks.^[5]
• Angle – A piton made of steel sheet bent into a "U", "V", or "Z" shape; works well for larger cracks, where the steel deforms elastically as the piton is placed.^[5]
• Bong – The largest pitons are angles made from sheet aluminum called a bong, named for the sound they produce while being hammered into place (or dropped). Largely replaced by camming units and nuts (chocks) that perform better and without damaging the rock.^[5]

• 
  Wired Chouinard RURP
• 
  Knifeblade pitons
• 
  Soft Metal Lost Arrow
• 
  Medium size Angle

Early pitons were made of malleable iron and soft steel and would deform to the shape of a crack when hammered into the rock, which worked well in the irregular cracks found on European limestone. Soft pitons are difficult to remove without damaging the piton, so they were left in place and became fixed anchor points on a climb.

During the exploration of the hard granite in Yosemite Valley in the 1950s and 1960s, it was found that soft pitons did not work well. The long routes developed in Yosemite made it impractical and costly to fix routes, and the soft pitons were not durable enough to be placed and removed more than a few times. Pitons needed to be removed and used again on subsequent pitches, sometimes many times. Leaving gear in place went against the ethics of many climbers. John Salathé pioneered designs using hardened steel which were much tougher than the European pitons. Salathé's pins, which he developed for a climb of the Lost Arrow, resisted deformation and were easier to remove and reuse, and were durable enough to be reused indefinitely.^[8]

• In the James Bond film For Your Eyes Only (1981), James Bond (Roger Moore) makes use of pitons while climbing a sheer cliff face, as a means to infiltrate the villain Kristatos' (Julian Glover) hideout. Just before he gets to the top of the cliff, Bond is met by Apostis, one of Kristatos' assassins. Apostis tries to kill Bond by knocking his pitons out of the rock, which would cause Bond to fall to his death. Just before Apostis knocks out the last piton, Bond unclips another piton from his belt and uses it as a throwing knife, injuring Apostis and sending the assassin falling to his death. Bond is then able to infiltrate Kristatos' hideout.
• Piton guns, fictional, handheld devices that shoot pitons into walls, appear in the 2004 Alien vs. Predator as part of the equipment of Charles Bishop's exploration team as they investigate what is revealed to be a pyramid where Predators breed and hunt Aliens. Team members use the guns to shoot pitons into the walls of the chasm being used to enter the pyramid, and after many of them are slaughtered in the central battle between the two species, the sole survivor, Alexa Woods (Sanaa Lathan), uses one to kill an Alien while escaping back to the surface with the last surviving Predator, Scar, whom she allies with.
• In the movie The Descent (2005), a piton is discovered while exploring an unknown cave system. The women find and use it to cross a deep hole, but the last woman falls when the piton breaks from the ceiling. When the piton is retrieved, it is clearly shown around 45 minutes into the movie, and one woman explains that the piton is over 100 years old and not used any more in modern cave exploration.

• In the video game I Am Alive, the main character can also use a piton to rest and replenish their stamina while climbing for extended periods of time.
• In Uncharted 4: A Thief's End, Nathan Drake acquires a piton from a hanged corpse. The tool becomes more used in the later half of the game. In Uncharted: The Lost Legacy, pitons left behind by enemy mercenaries are used by Chloe Frazer and Nadine Ross.
• In the Hitman World Of Assassination Trilogy, a Piton can be used as a lethal weapon to stab targets, acquired by purchasing downloadable content.
• Pitons are a central mechanic of the 2023 climbing / puzzle platforming video game Jusant.
• In Firewatch, pitons are used by the main character Henry to descend down a steep gravel incline. An incorrectly sunk piton is also the reason for Brian Goodwin's death, according to his father, Ned.

• Dan Simmons' historical fiction novel, The Abominable (2013), centers on mountain climbing and frequently depicts passages in which piton use is crucial (e.g., Chapter 5). Additionally, the world-class British Alpinist, Richard Davis Deacon, sneers at the Germans' heavy use of such equipment, while the narrator, his younger American protégé, deems it brilliant (Chapter 6).

• In the MacGyver season 2 episode "Eagles", MacGyver must climb a mountain to save baby eagles. Short of equipment, he uses tent stakes as pitons.
• In The Alienist season 1 episode 4 ("These Bloody Thoughts"), the Jewish twins who work on the case discover a metal tool on the ground of the crime scene (the old immigration station, also known as the battery). One of the twins, Marcus, finds a piton on the ground, which was used by their suspect.

• Aid climbing
• Big wall climbing
• Bolt
• Copperhead
• Grappling hook
• Kaginawa
• Kyoketsu-shoge
• Rock climbing equipment