Aluminumis significantly lighter than steel and is therefore far more popular in the outdoor and climbing industries where weight is a major factor.
Auto-locking carabiner uses an internal spring mechanism to not only close the carabiner but also lock the carabiner as soon as the gate is released.
Screw Locking gate is the most common. A sleeve must manually be loosened to unlock or tightened
Pin Nose Gate is a notch in the nose of the carabiner to maintain its structure and strength. This nose type is typically stronger.
Modified “D” shape This shape helps to push the load to the back of the “spine”. Allows weight to be carried primarily by the spine and less by the gate—making for a stronger and lighter use.