This four-pack of Anchors from Peak Design serve as replacement or spare parts for the Leash and Cuff. They can be attached to any loop or D-ring by tying a cow hitch knot. The small circle on the end of the anchor slips into the slot on the end of the Leash or Cuff and locks into place. It is released by a one-handed push of a button. The Anchors are made from Dyneema fiber overmolded with Delrin thermoplastic, can hold up to 100 lb, and are more wear-resistant than previous models. The outside sheath is black, the middle yellow, and the inner sheath is red; when you start seeing yellow, it's time to replace your anchors.