A quick and easy method of attaching your leader to the fly line. Simply slide the barbed portion of the eyelet into your fly line and you are able to add or change leaders quickly. Per 15. Sizes: Small - 3, 4, 5 wt. fly lines, Large - 6, 7, 8, 9 wt. fly lines. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Leader Connectors.