I've tried everything for leaders when fishing pike on the fly. I’ve lost numerous flies with fluorocarbon but wire has never let me down. Now there’s wire and then there’s this stuff Cortland Toothy Critter, its wire you can tie with a regular knot. No special tools needed no hassles and you can repair it or tie it streamside or in the boat. The best part is that it has never broken on me, never left one of my favorite flies in the jaws of the snot rocket. It's a little pricey up here in Canada at $10 for a 10 foot piece but worth every cent when you don’t lose your favorite fly.