A d-ring is used for clipping and securing equipment with clips. It is composed of a ring bent in a D shape and usually made of resistant material like stainless steel or very hard plastics. They are positioned mostly on the shoulder straps but can also be hanging from the side flaps of jacket or hybrid style BCDs or on the waist straps on harnesses to give other options then the shoulders.

Another use of D-rings is to help divers to grip and pull the straps on the various adjustable points of a jacket or harness BCD.