Scientific Anglers Dacron Backing 100-250yd

As the first layer of line for your fly reel, backing is a braided line fashioned from alot of smaller strands and an essential part of fly fishing.

Backing is essential for two reasons. Filling up your reel, to allow for faster reeling of your line and if you hook a large fish, the fish needs to be allowed to run. Backing allows the fish to move more without your line breaking.