Shimano's Hagane reel design concept

"HAGANE is a Shimano reel design concept created to withstand continual use and extreme abuse. HAGANE is an innovation of built in toughness and durability, working alongside Shimano's precision engineering. As you evolve, we evolve." http://fish.shimano.com/content/sac-fish/en/home/products/info/technolgies.html