Baitcasting Rod Reel T What is backing as used as a filler on a baitcasting reel and where can I purchase it? by Captain David M Rieumont 17.7k Views Sorry this content is for subscribers only Subscribe to continue reading. Already a subscriber? Sign in Thanks for reading TheOnlineFisherman.com Try one month for $1 Login See more Previous article What is “Backing” and do I need it? Next article What is best line to use for an open-face reel?