Cabela's Prestige Fly Line Backing - 200 Yards Reviews:
Seems to do the trick, I fish on the Delaware River and do get into my backing on a good day. I like the white line and used the extra to hang painted fish cut from 1/2" plywood at our 5th annual One Bug Fundraiser this year. The fish look like they were swimming in the sky!
This was a very economical way to obtain my needed backing. Solid product and can't wait to try out my new rod, reel and fly line. When fishing for salmon out in western Washington, you need all the extra backing you can provide.