Black Diamond designed the 13mm Dynex Rabbit Runner for threading icicles on ice climbs or extending trad gear on wandering rock climbs. It has two different sized pockets; one is smaller than the other to stabilize carabiners, and the other is larger so you can girth-hitch a lot easier. This single strand offers a full-strength of 22kN, and it's a lighter, more compact alternative for extending gear.