A fly fishing sling pack is a great option if you don’t want to carry a backpack. The easiest way to organize it is to ask yourself which gear you will need at the water. Most of the time, you will want to bring several fly boxes, including a nymph box, a streamer box, and a dry fly box. Your sling pack can also hold additional items such as tippet spools, pliers, sink leaders, or a pair of fishing sunglasses.