Carabiner with screw lock 25kN

A carabiner is a D-shaped piece of metal (typically steel or aluminum) that has a spring-loaded closing mechanism on one side.
It was originally designed for climbing and mountaineering to connect ropes with climbing elastics, but its use has since expanded to many other purposes.

There are basically 2 different types of carabiners:

1. Safety carabiners: These are primarily used for climbing and other safety devices. They are designed to carry heavy loads and often have a locking mechanism to ensure the lock does not open unintentionally and some have printed standards with max load on the carabiner. 

2. Non-safety carabiners: These are often lighter, cheaper, and used for general purposes such as keychains, attaching items to backpacks, and many everyday situations.
   They should not be used for climbing or other safety-critical purposes.
   
   

This carabiner falls under the category of safety carabiners.

Carabiners have become popular due to their versatility, durability, and ease of use. Whether you are a climber, hiker, or just need a practical way to keep things together, a carabiner is a useful tool to have on hand or in your backpack.