Round nose pliers

Round nose pliers have two smooth, cone-shaped jaws that taper from wide at the handle end to narrow at the tip, with no flat gripping surface. That shape is what lets them bend wire into a round loop, since the wire simply curves around whichever point on the cone it is wrapped around.

Where on the jaw the wire sits controls the loop size: closer to the tip makes a small loop, further back toward the handle makes a larger one. Because the two jaws taper at slightly different rates, marking a spot with a permanent marker helps make loops the same size across a batch of earrings or a matching set.

When buying, look for smooth, unmarked jaws rather than ones with a serrated or ridged texture, since texture leaves dents in soft wire. A common mistake is squeezing too hard while forming a loop, which flattens or dents round wire; the jaws are meant to guide the bend, not clamp it.