An oval shaped metal loop with spring loaded gate. Used to attached the rope to items of protection. They come in numerous forms: HMS, screwgate, snaplink, wire gate.
Generally an oval or D-shaped device of lightweight aluminium or alloy that serves as the climber's all-purpose connector. It has a spring-loaded gate through which a climbing rope can be threaded. The most basic all-around tool on a climber's rack, they are used variously for such activities as belaying, abseiling, and clipping into safety anchors.
Universal linkage for ropes. etc.
A metal chain like link but with a spring loaded gate on one axis.
A metal loop that can be opened or fastened closed. Used to attach ropes to anchors or cavers to descenders or ropes etc.
An oval metal hoop with a springloaded "gate". Rope and protection are attached to karabiners. Also known as a "krab". Karabiners come in many forms, and arguments about which is best occupy many hours in gear shops.