While some climbers may debate that rock shoe or a harness are the most important piece of equipment for rock, they may be overlooking the significance of the carabiner.

Coming from a German word that means “hook for a carbine,” the metal loop with a sprung or screwed gate plays a larger role in rock climbing than some may think.

“Carabiners are used as links in the climbing chain or system,” said Merit West, rock wall supervisor for Life Time Fitness in Chanhassen, MN and regional training specialist.

“Without (the carabiner) you can’t create the links in the system that you need,” West said.

If people tried to climb without carabiners, West said, chances are their climbing gear would be damaged in a hurry.

“You should never combine unlike materials,” West said. In climbing’s case, those materials are cordage from a climbing rope and webbing from a climbing harness.

When those two rub together enough without a buffer between them, he said, a climbing rope and harness could “saw right through each other.”

“That’s where the carabiner comes in,” West said. “The carabiner being a piece of metal is able to withstand the abrasion. So it is used as a link between unlike materials.”

Carabiners are used for many climbing purposes such as clipping into belay and rappel anchors, rigging a belay or rappel device, carrying gear on a harness or gear sling or connecting gear to a rope for hauling, West said.

In essence, the carabiner is a multi-purpose tool that plays a large role in climbing.

But before getting into the different kinds of carabiners, West said, a climber must understand the anatomy of a carabiner.

The major sides of the carabiner are the gate and the spine, West said. The gate is what allows either a rope or other object clip into the carabiner.

Each carabiner is also marked with a strength rating for holding a load, West said. Generally, these ratings are very high, West said, but it does not mean a carabiner cannot be damaged or broken if it is loaded improperly.

Carabiners are designed to be loaded along their major axis (end to end) with the gate closed and any carabiner with its gate open is reduced in strength dramatically, West said.

“You want to make sure that the gate snaps closed,” West said.

Carabiners come in an assortment of shapes and styles, West said. The most recognizable carabiner shapes are the oval , D-shaped, offset-D, and pear/HMS.

The two major styles of carabiners, West said, are locking and non-locking. The two kinds of locking carabiners either have a spring-loaded auto-lock capability or a screw gate lock.

With non-locking, there are the straight gate (which is the most common), the bent gate and the wire gate.

Originally, West said, carabiners were only made out of steel. “But those can get really heavy, especially when you’re carrying 20 of them.”

Today, most climbing carabiners are made out of alloys, particularly aluminum, West said, because they are a lot lighter but do not sacrifice strength.

However, West said, the life of aluminum carabiners are much shorter than steel because the material can damage easier from regular use. West said Life Time Fitness clubs change their carabiners annually because of the daily, consistent use of them at the rock walls.

“That’s a very high rate of use, so they’ll last about a year,” West said.

For those new climbers looking to dive into the sport, West said they only need one kind of carabiner.

“Most climbers who won’t be outside climbing … really the only carabiner they’re going to need is a nice-sized locking carabiner,” West said.

With a locking carabiner, West said, always perform the “Squeeze Test,” which involves the climber squeezing the spine and gate of the carabiner in their hand, to double-check that it is locked.

And novice climbers should always hook up two carabiners to their harness, just in case one malfunctions or opens by mistake, West said. When using two carabiners, he said, climbers should also make sure the gates are opposing each other.

For the outdoors, West said, climbers could need anywhere between 20 to 40 carabiners, sometimes carrying at least three different styles, to carry protections (devices that aid a climbing ascent) while climbing the rock.

“Make sure you have enough and extra,” West said. “… Otherwise you’re going to find yourself in a situation where you have to make a choice.”