Fly Line Backing - Troutster Premium Fly Fishing Line Backing | 20-30 Pound Test | 50 or 100 Yards Length Fly Backing - Color: Yellow or White - Fly Reel Backer Fits All Types of Fly Fishing Reels; Fly Rod Backing for Trout, Bass, Pike, Salmon, Steelhead and More. Available in 20 or 30 lb. Test. Great for trout, salmon, steelhead and other large fish. Super strong and smooth. Will fit on any fly fishing reel. Supreme knot strength.