Activities The Great Outdoors All About Carabiners Carabiners are Essential Climbing Equipment Print Carabiners come in lots of different sizes and shapes. Buy a reputable brand and your carabiners will keep you safe on the rocks. Photograph copyright Stewart M. Green The Great Outdoors Climbing Gear Basics Highest Mountains Skiing Snowboarding Surfing Paddling Fishing Sailing Scuba Diving & Snorkeling By Stewart Green Stewart Green Stewart M. Green is a lifelong climber from Colorado who has written more than 20 books about hiking and rock climbing. Learn about our Editorial Process Updated on 03/17/17 Carabiners are a basic and essential piece of equipment that you use every time you go rock climbing. A carabiner, the work horse of a climber's rack of gear, is simply a strong metal snap-link made of lightweight aluminium or hefty steel that is used to connect all the different parts of the climbing safety system together. Carabiner Gates Carabiners, often called "crabs" and "biners," have a spring-tensioned gate that opens under finger pressure, making it easy to clip it to climbing gear like a rope. The spring inside the carabiner normally holds the gate closed. The gate is pushed open with the fingers to allow a rope or other equipment to be clipped to it and then snaps shut when released. Carabiners are strongest when the gate is closed and weakest when the gate is open. Climbers often used locking carabiners, or carabiners with a gate that locks shut whenever they want to make sure that nothing comes unclipped from the carabiner. Use Carabiners for Safety Carabiners perform a wide variety of climbing tasks, including attaching a climber to a rope, attaching a climbing rope to a harness or piece of gear like a cam (SLCDs) or climbing nut, for attaching a climber to a belay anchor, and for attaching a climber to a rope for rappelling. Carabiners are super strong because our climbing safety depends on them. Carabiners Come in Lots of Shapes & Sizes Carabiners come in a wide variety of shapes and sizes and which ones you buy and use depends on how and what you climb. Any carabiner made by a brand name manufacturer like Petzl, Black Diamond, Metolius, and Omega Pacific, is safe, sturdy, and will last a long time if properly used. Only Use UIAA-Approved Carabiners Carabiners, along with other equipment like harnesses, ropes, and cams, are constructed to meet stringent standards set by the UIAA (International Mountaineering and Climbing Federation). Always buy UIAA-approved equipment because you know it's certified and safe. Carabiners are rated for strength by kilonewtons, a measurement of the severe forces applied to the equipment by a climbing fall. 3 Basic Carabiner Types Carabiners come in three basic shapes—-oval, D-shaped, and asymmetrical D-shaped—-and have three basic types of gates-straight gate, bent gate, and wire gate. There are two types of locking carabiners--auto-lock carabiners and screw-lock carabiners.