They connect the anchor to the chain cable between the Crown Shackle and the End Link (E). Like the other accessories, Adamar Anchor & Chain offers Anchor D-End shackles in all sizes between 30 mm and 102 mm.
Customers frequently mix crown Shackles and Anchor D-end shackles. Just a tip to identify them: Crown Shackles are permanently connected to the anchors, and their pins are round. However, Anchor D-end shackles have oval pins, and they are removable.