Shimano’s "MGL SPOOL Ⅳ" features a reverse-tapered shape that is ultra-thin and designed for extremely low inertia.
It winds the line evenly and consistently. A well-spooled, balanced spool reduces spool vibration during casting, resulting in improved performance.
Advantages of Low Inertia Spools
Shimano is dedicated to minimizing the inertia of spools, as this reduction can significantly enhance the performance of baitcasting reels. A low-inertia spool enables a rapid acceleration of rotation, allowing anglers to cast lightweight lures swiftly and with less effort.
Shimano has consistently refined the design of spools for baitcasting reels.The "MGL SPOOL III", represents the third generation of these advanced spools. This model boasts significantly lower inertia compared to its predecessors, enhancing performance and casting efficiency.
Effortless Long and Low-Trajectory Short Casts
Comparison of the cross-sections of MGL SPOOL II and MGL SPOOL III
The figure illustrates a comparison between the cross-sections of "MGL SPOOL II" and "MGL SPOOL III". Notably, "MGL SPOOL III" demonstrates a remarkable reduction in inertia while maintaining exceptional durability, showcasing advancements in thin-walled spool design.
This low-inertia spool rotates effortlessly, enabling longer and smoother casts. This capability extends your reach to distant targets that would typically be unattainable, significantly enhancing your chances of attracting bites. Additionally, it allows anglers to execute precise, low-trajectory casts with exceptional accuracy.
This spool has successfully reduced weight without compromising its remarkable strength, elevating your casting experience to new heights. Once you cast with it, you’ll truly feel the difference.
The figure illustrates a comparison between the cross-sections of "MGL SPOOL II" and "MGL SPOOL III". Notably, "MGL SPOOL III" demonstrates a remarkable reduction in inertia while maintaining exceptional durability, showcasing advancements in thin-walled spool design.
This low-inertia spool rotates effortlessly, enabling longer and smoother casts. This capability extends your reach to distant targets that would typically be unattainable, significantly enhancing your chances of attracting bites. Additionally, it allows anglers to execute precise, low-trajectory casts with exceptional accuracy.
This spool has successfully reduced weight without compromising its remarkable strength, elevating your casting experience to new heights. Once you cast with it, you’ll truly feel the difference.
"MGL SPOOL Ⅳ" rotates more smoothly when casting.
The balance of the spool with the line wound on it has a significant impact on cast-performance.
Building on the advancements of the "MGL SPOOL III", which emphasizes low inertia through its ultra-thin design, the newly developed "MGL SPOOL IV" takes performance to the next level. It has achieved an optimal spool shape with a unique reverse taper design, enhancing both functionality and efficiency.
The spool, expertly designed for balanced line winding, minimises shaking during rotation and significantly dampens vibrations while casting. This innovation delivers an exhilarating casting experience, making it feel as though the line is effortlessly unfurling into the distance.

Our goal, effortless reeling.
Shimano's reel design concept aims for "eternally smooth reeling". The result is HAGANE. Shimano honed its proprietary metal processing technologies with precision cold-forging technology and refined them over many years to develop reels that only Shimano could deliver.
Shimano's Digital Control technology utilises a microcomputer to manage the braking force. As a result, the released spool delivers an impressive casting distance, enhancing your overall fishing performance.
Shimano’s "DC (Digital Control) BRAKE" system quickly detects changes in spool rotation and adjusts the braking force using a microcomputer. This advanced braking system allows for impressive casting distances while minimizing line issues.
Versatile brake system: Adjust on-the-fly with an external dial for any situation.
The SVS centrifugal brake system offers precise casting capability thanks to its exceptional casting accuracy. This design allows anglers to hit their intended targets effortlessly, enjoying the benefits of lightweight reels that enhance performance with exciting line leaps and long-distance casts.
Introducing the lightweight revolution: The new concept magnet brake system.
The Finesse Tune Brake (FTB) system, which is adopted in Shimano’s bait reels, is a magnetic brake system that eliminates the brake unit from the spool, making it the lightest spool in Shimano’s bait finesse history.