Hollow threading needles, loop needles, and latch needles for making wind on leaders, top shots and virtually seamless connections between braided lines and braided line to leader. The Treading needles are hollow except for the point. This allows you to insert the mono or fluorocarbon into the needle and then into the hollow braid. The loop needles are used for making loops in the braid or for "opening up" braid for insertion of other needles or leader directly. The Latch needles are also designed for making loops with techniques that require you to release the braid during the process. Use the size chart below for guidelines as diameters vary between manufacturers.