Carabiners are metal loops made of aluminum or steel that come in a variety of shapes and sizes a have various spring locking and non-locking gates. They are commonly used in mountain and rock climbing, rappelling/ abseiling, sailing, tree climbing, fire and rescue, and industrial work like construction and window washing. There are several different types and grades of carabiners and rating standards for safety. The American National Standards Institute (ANSI) sets standards for products in the United States while working in conjunction with international organizations. A carabiner used for life attachment should conform to ANSI standards. These carabiners will meet certain strength requirements and functionality, such as auto-locking and auto-closing. Other ANSI safety requirements call for the carabiner to unlock only by two distinct actions, with a third action required to open it. Carabiners in this category must also meet a minimum strength requirement of 5,000 pounds (24 kiloNewtons). Many aluminum and steel carabiners meet these standards, though aluminum is favored for mountain climbing because it is lightweight. Specification covers six mechanical tests, one corrosion resistance test, and the minimum performance requirements for these tests. This specification applies to carabiners designed specifically for use by rescue personnel during both training exercises and actual rescue operations. This specification does not apply to recreational use carabiners. Accessory carabiners used for rigging and similar purposes are not required to meet the ANSI standards for life support.

Steel carabiners, generally stronger than aluminum, are often used when the weight of the carabiners themselves is not an issue.Manufacturers usually stamp the breaking strength of a carabiner onto its side. This rating reflects the minimum force required to cause the carabiner to fail. Carabiners are tested in two ways: for vertical strength and for side-load, though generally carabiners are not intended to bear side-loads. Since the rating is based on force rather than weight, the numbers refer to kilonewtons instead of pounds or kilograms. A sufficiently accurate conversion to pound force can be obtained by multiplying kilonewtons by 220; giving a carabiner rated at 25 kilonewtons roughly a 5,600 pound force rating. Carabiners are light, strong, inexpensive, and handy -- even around the house, workshop, or office. Many people use carabiners for key rings or hammock rigging, or for hanging tools. They are also used for waterski lines, camping equipment, and a multitude of other applications.

Carabiners are available from sporting goods shops, outfitters, marine and boating retailers, and recreational outlets of all kinds. Brightly colored carabiners are often displayed by the checkout registers of home improvement centers, though these are intended for simple uses that do not require safety considerations.

Tips and Tricks:

Clean carabiners with soap and water and then dry with compressed air. Lube gates with a silicon spray. Use of oil lubricants can damage rope and webbing.

Damage to aluminum carabiners often occurs from the inside out and thus major damage can go undetected. Extra care should be taken for aluminum carabineers that are going to be used in rescue/critical applications.

Steel carabineers in terms of their wear and tear tend to last much longer than aluminum.

Using aluminum carabiners against steel (ie on a steel D-ring on a raft) over a prolonged time can cause damage and possible failure of the aluminum carabiner.

Prolonged use of a steel carabiner on aluminum can cause the aluminum to be damaged (ie a steel carabiner directly attached to an aluminum sand stake).

Cross loading a carabiner decreases the force that can be put on the carabineer greatly and should be avoided.