D-shaped ring, named after its shape like the letter “D”. It is very versatile. Often used on the strap to fix the water pipe, or hang some small objects
There are not many types of D-rings. The curvature is very smooth, suitable for picking with your index finger or thumb, so some bags will design the D-ring in a place where it can be used to support the force. For example, a larger travel bag (Travelbag) strap will have a D-shaped ring on the front right, this design is to use the right hand to support after the bag is too heavy.
Sometimes the D-ring is used in the plug-in system.