These devices are a gated connecting device used in rock climbing to attach a rope to a fixed anchor, tie in to protection points and the Belay Device. They are which are either non-locking or locking, and hinged with a spring to snap shut when released. They are lightweight, most commonly made with aluminum, and specifically designed to be operated with one hand. They are built to withstand a high shock force, and yet are light enough for climbers to carry between 6 to 30 without being hindered by the weight or bulk. The sizes range from big 3.7 ounce--to the mini 1.2 ounce aluminum carabiner. There are three basic types:
Snap Gate Aluminum Carabiner
Oval. The semi-circle at each end distributes the load while allowing the rope or another carabiner to shift with movement. Typically these are the least expensive, lightest in weight to include the mini size. The tradeoff is they are not as strong and a little more difficult to clip than other styles, but are is ideal for clipping gear and rack items to the climbing harness.
"D" - Symmetrical. The "D-shape" causes the connecting runners or rope to shift toward the spine side (away from the gate). The spine side of the aluminum carabiner is stronger than the gate. This type will take more shock and weight force than the standard oval. They are easier to clip into runners and anchors points than the oval. This type works well for lead and top rope clipping.
"D" - Asymmetrical. The asymmetrical function provides space for a larger gate opening. This facilitates clipping and reduces weight a little. The asymmetrical has a larger gate opening than the symmetrical, but has less space inside the carabiner. It is also a good choice for lead and top rope clipping for experienced climbers.
Type of Gates, Gate Options
- Straight Gate. These are straight as the name implies. This is a little less expensive than the bent gate, more common and offers good functionality.
- Bent Gate. This type of gate has a slight concave curve. The purpose is to provide more room for the rope, runner or anchor point which allows faster clipping. Some climbers believe this type of gate is slightly more prone to unintentional unclipping. This could happen if another carabiner or protection point is twisted against the gate. For this reason, the bent gate type should be used with a runner or quickdraw. When used properly these provide added advantage of easy, smooth and quick clipping.
- Wire Gate. The thinner gate of the wire is an advantage in two ways: It provides more room, and is not as susceptible to "gate lash". Gate lash is the momentary opening of the gate caused from jarring or impact during a fall. This momentary opening weakens the carabiner at the instant of impact stress--when the full strength is needed most. When the gate is closed the gate contributes to the overall strength. When the gate is open, the spine carries the full strength. This is called open gate loading. Open gate loading is the leading cause of failure of aluminum carabiners. Since the wire gate has less momentum than the other gates it is less prone to pop open on impact.