By providing dependable sealing structures and gaskets at 12 critical locations throughout the reel body, Shimano is able to create a water-resistant structure that is highly reliable and durable while ensuring that it can hold up when used in extreme saltwater conditions.

Large reels for saltwater, a contact-type water-resistant structure is used for large spinning reels that require higher water-resistant performance. By physically cutting off the entry path of seawater with a low-sliding seal member, high water-resistant performance is achieved while suppressing rotational resistance. The stopper bearing and line roller parts are adopted, and the stopper bearing part in particular achieves a water-resistant rating equivalent to IPX8.

Shimano designed the Anti-Twist Fin for enhanced line management resulting in more effective fishing. The flexible polymer fin is installed near the line roller. This maintains line tension to reduce sagging and prevents the line from falling off the bottom of the spool or wrapping around the spool in an uneven manner.

InfinityLoop technology delivers exceptional casting performance by drastically reducing friction on the line leaving the spool. Advancements in the internal structure and design extend the spool's oscillation to enable the spool to move up and down at an extremely low speed. This technology creates a precise winding pattern with less overlap that significantly reduces friction as the line leaves the spool during a cast. The result is smooth and exceptional casting performance, especially of light lures.

InfinityXross provides superior gear durability through industry-leading design and cutting-edge manufacturing technology. Advancements in the gear tooth design improve the surface contact and meshing between the drive gear and pinion gear. This revolutionary design efficiently distributes the load placed on the gear tooth surface across a wider area to prevent damage from stress points while significantly improving overall gear durability.

Each washer is made of metal and carbon. Larger diameter drag washers have been installed on both the top and bottom sides of the spool. As a result, smooth and stable drag performance has been enhanced by improving heat resistance and durability.

By strengthening the spool support of the main shaft, the play and fluctuation of the spool during drag operation are suppressed. The Rigid Support Drag allows smooth and consistent drag delivery, even under high load.

The spool has a special spool ring shape. This creates a rectifying effect on the line and realizes both suppression of line trouble and long casting performance.

By using aluminum alloy and verifying the thickness arrangement in detail through repeated 3D analysis, we have achieved stronger rigidity, durability and excellent rotational balance than ever before. This high rigidity also contributes to improving the functionality of the drag and other parts.

A high-rigidity cold-forged handle made exclusively for Stella SW that transmits the angler's power without any loss.

To increase rigidity, the arm cam is made of metal, just like the rotor. It transmits the power of the Stella SW without distortion when winding the line under high load or when dragging. The metal plating process maintains a smooth surface for a long time. It reduces damage to the line.

Special treatment (diamond-like carbon) on the surface reduces friction and prevents line wear. Also, it is equipped with a contact-type waterproof seal that blocks seawater from entering the line roller. It protects the internal bearing from harsh environments and is more than 10 times more durable than models without it. *Based on our comparative tests.

The line roller, which is the first to receive the pull of a large fish and receive the force, is equipped with a mechanism to prevent loosening. To make the bolts that secure the line roller even more difficult to loosen, they are doubly fixed with set screws.

The handle knob is made of CI4+ carbon material, which is both highly rigid and lightweight.

One-Piece Bail allows the line to travel unimpeded to the line roller. The seamless design reduces friction and decreases the chance of tangles or the line catching on the bail arm.

The 25 Stella SW has been improved in detail with a drag knob that is 25% larger in diameter to further improve operability. This not only makes it easier to grip the knob for quick operation, but also makes it easier to make fine adjustments. This provides an advantage when tightening or loosening the drag instantly when a large fish is hooked.

The handle knob also has a waterproof structure.