Climbers usually work in pairs, with one climbing and the other belaying. In lead climbing, the belayer feeds rope to the lead climber through a belay device. The leader climbs up, occasionally placing protection or clipping preplaced bolted hangers, until the top is reached. The belayer is ready to "lock off" the rope if the leader falls.

Both climbers attach the rope to their climbing harness, usually tying into their harness with a figure-eight knot or double bowline knot. The leader either places protection or clips into permanent protection already attached to the rock usually called "bolts". In traditional climbing, the protection is removable. Usually nuts or Spring-loaded camming device (often referred to as "cams" or "friends") are set in cracks in the rock (although pitons are sometimes used). In sport climbing the protection is metal loops called hangers or bolts. Hangers are secured to the rock with either expanding masonry bolts taken from the construction industry, or by placing glue-in bolt systems. In ice climbing the protection is Ice Screw or similar devices hammered or screwed into the ice by the leader, and removed by the second climber.

The lead climber typically connects the rope to the protection with carabiners or quickdraws. If the lead climber falls, he will fall twice the length of the rope out from the last protection point, plus rope stretch (typically 5% to 8% of the rope out), plus slack. If any of the gear breaks or pulls out of the rock or if the belayer fails to lock off the belay device immediately, the fall will be significantly longer. Thus if a climber is 2 meters above the last protection he will fall 2 meters to the protection, 2 meters below the protection, plus slack and rope stretch, for a total fall of over 4 meters.

If the leader falls, the belayer arrests the rope. This is achieved by running the rope through a belay device attached to the belayer's harness. The belay device runs the rope through a series of sharp curves that, when operated properly, greatly increase the friction and stop the rope from running. Some of the more popular types of belay devices are the ATC Belay Device, the Figure 8 and various auto-locking belay devices such as the Petzl Gri-Gri

At the top of the pitch, the leader sets up a secure anchor system, also called a belay, from where he can belay as his partner climbs. The second climber removes the gear from the rock (traditional climbing) or removes the quickdraw from the bolted hanger (sport climbing). Both climbers are now at the top of the pitch with all their equipment. Note that the second is protected from above while climbing, but the leader is not, so being the leader is more challenging and dangerous. After completing their climb, with both climbers at the top of the pitch, they must eventually rappel or otherwise descend the climb in order to return to their starting point. But all climbs do not necessarily require the lead climber to belay the second climber from the top. The belayer could lower the lead climber down after he/she has completed the pitch.

Occasionally, climbers may decide to "move together", a risky but speedy technique also called simul-climbing, in which both leader and second move at the same time without stopping to belay. The leader - approximately a rope length above the second - usually places multiple pieces of protection as he climbs so that the weight of the second climber might arrest a possible leader's fall. Should it be the second climber to fall, however, the leader may be pulled from his holds, with potentially unpleasant results.

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