I'm afraid they have all gone away from supplying spare spools these days.
Always purchased Stradics in the past for Walleye fishing. Carried one spool loaded with 6# Firleine and the other with 4# Fireline.
Of course, fishing the Salt, carrying a spare spool was a good idea because you never know when you might have something smack your bait that will spool you in a heartbeat!
