Orvis Braided Dacron Backing for Fly Reels- Orvis Fly Line Backing is braided white Dacron on spools and is precision processed with uniform strength. Twelve pound test is for light lines and smaller reels. Twenty pound test is for trout, bass, and most freshwater fishing. Thirty pound test is for salmon and saltwater applications. Choose what you need or have us spool up your reel; new or old.