Shielded Stainless Steel Anti-Rust Bearings. These bearings have undergone a special heat treatment resulting in high metal strength. Shielded A-RB bearings use either a rubber shield or stainless steel shield (depending on bearing size) for the ultimate in corrosion resistance and contaminant protection against sand, salt or dust.

Hagane is a Shimano reel design concept created to withstand continual use and extreme abuse. Hagane is an innovation with built-in toughness and durability that works alongside Shimano's precision engineering.

With amazing strength and durability, the HAGANE Gear is at the very heart of most Shimano reels. Shimano, through the application of state-of-the-art technologies, gives anglers the long-lasting smoothness and pleasure that is felt when anglers first use a reel, over and over again. No cutting work is applied to the teeth of the drive gear during fabrication, instead the entire surface is calculated in minute detail by special 3D-design and then formed by Shimano's cold-forging technology. 

The HAGANE Body is a metal reel body with high rigidity. The body rigidity and impact resistance virtually eliminates body flexing on the reel while fighting fish. The result transforms the angler's actions directly into cranking power, increasing efficiency through strength.

CI4 is a Shimano original material reinforced with carbon fiber that is lighter and has a higher strength than conventional resin material. CI4+ is an advanced version of the original CI4 material and is 2.5x more rigid than its predecessor. While improving lightness and rigidity, reel bodies and rotors built with CI4+ are further reduced in size and weight.

X SHIP provides improved gear durability. By supporting the pinion gear on both ends with bearings, the pinion gear maintains precise alignment with the drive gear. This increased support allows the gears to stay in the same position under the heaviest loads. X-Ship technology also eliminates the friction between the spool shaft and gear to further benefit anglers with enhanced casting performance and casting distance of lighter lures.

S3D (SHIMANO STABLE SPOOL DESIGN) leads to significantly reduced spool vibration. This creates an smooth feeling when casting.

Shimano developed the Finesse Tune Brake (FTB) to improves casting performance of lightweight lures by eliminating the brake unit from the spool. This revolutionary design further reduces weight beyond traditional spool-porting designs that keep the brake unit attached. When the spool rotation speed increases, these magnets move outward to the spool closer.The backlash is prevented from the increased Brake power.