Insertion Pin: Insertion Pin (插销)
The stiffened rod at the end of one tape on an open-end zipper. It is inserted into the box on the opposite tape so that both chains align before the slider is pulled up. Pin thickness, length and tip shape control insertion feel and pull-out resistance. A pin that is too short or too soft bends easily, causing difficult starting and premature separation. Metal pins are stamped and resin pins are moulded onto the tape.