Black Diamond Micro Stoppers are ultra-thin protection for aid climbing and thin trad lines. Copper-infiltrated steel heads fight shearing better than solid copper but are soft enough to prevent breaking the rock. The heads are swaged onto the cables, providing a more durable attachment than soldering. With Micro Stoppers youll be able to sew up the thinnest cracks, even if you cant get your fingers in them. Sizes 1 and 2 are meant for aid climbing only.