Slow-extruded in Japan
A controlled process helps keep the diameter uniform and the surface clean.
Big Game Series Ā· Slow-extruded in Japan
Opsin Big Game 300 lb Fluorocarbon Leader
1.84 mm Ā· 30 m and 110 m
At 1.84 mm, Opsin 300 lb is the top end of the Big Game lineupābuilt for maximum abrasion resistance, heavy drag, and the fish that expose every weak point in a leader system. Slow-extruded in Japan for consistent diameter, dependable crimping, and controlled handling at the rigging bench.
Maximum class. Repeatable connections. Built for the hardest jobs.
Rigging note: Match sleeve and crimp cavity to the measured 1.84 mm diameter. Start by bench-testing a Diamond Silver Lock E sleeve at 2.0 mm, then pull-test the complete system.
UV-blocking metallized bagProtects the coil from light exposure and storage abuse.
Developed in the U.S. Ā· Made in JapanBuilt around real offshore rigging needs and Japanese production.
No-BS supportTalk to someone who understands the line and how it fishes.
The material
Strength without unnecessary bulk
At this diameter, small inconsistencies become big rigging problems. Slow Japanese extrusion helps keep the 1.84 mm profile controlled so crews can build heavy leaders with repeatable sleeve fit and compression.
Thin by design
Less unnecessary bulk in the leader, with serious big-game capability.
Supple where it counts
Lets live bait move naturally instead of dragging a stiff leader through the water.
Built for clean rigging
Consistent diameter supports repeatable sleeve selection and crimp setup.
Where 300 lb fits
Choose the leader for the job
300 lb is the maximum class in the Opsin lineup for giant tuna, marlin, and heavy wind-ons where protection and sustained load come before bait finesse.
| Line class | Diameter | Best for |
|---|---|---|
| 100 lb | 0.93 mm | The thinnest Big Game profile for natural bait presentation and lighter drag |
| 130 lb | 1.06 mm | Finesse-minded heavy tackle and cleaner bait presentation |
| 150 lb | 1.18 mm | Heavy tuna and versatile big-game rigging |
| 170 lb | 1.28 mm | More abrasion margin and higher-drag applications |
| 200 lb | 1.44 mm | Heavy drag, bigger hardware, and more insurance when the leader gets rubbed |
| 250 lb | 1.57 mm | Heavy leader work where abrasion margin matters more than finesse |
| 300 lbYou are here | 1.84 mm | Maximum leader class for the heaviest tackle and highest-abrasion rigging |
Angler proof
Proven across the Opsin line
Real feedback from anglers fishing Opsin fluorocarbon from light leader to heavy offshore classes.
Opsin fluorocarbon customer reviews
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āUse Opsin from 2 to 180 lb. Trout to tuna. Works great, holds, stealth and gets bites when the bites are hard to come by.ā
Issac ParsellOpsin fluorocarbon
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āI use this product primarily for yellowtail and tuna. The product works great. Opsin has been my go to fluro for the past six years.ā
Robbie RobinsonYellowtail and tuna
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ā50lb opsin is the bomb. You can really pull with confidence and it paid off for me on my 8 day trip on the Indy!! 104lbs!ā
Ned Nakatsuka8-day trip Ā· 104 lb fish
Verified customer reviewRigging notes
Crimp it like the whole system matters
What sleeve should I use with Opsin 300 lb?
Treat 300 lb as its own maximum-class rigging system. Opsin 300 lb measures 1.84 mm. Diamondās published tool guides place its 2.0 mm E Silver Lock sleeve at 1.8ā1.9 mm mono or fluorocarbon, making it the cleanest documented first bench test.
A 2.2 mm Diamond copper double sleeve is an alternate only where the exact tool guide covers 1.8ā1.9 mm. Match the cavity and pull-test the complete leader before fishing.
Diamond Silver Lock E Ā· 2.0 mm
Diamond publishes the E sleeve for 1.8ā1.9 mm mono or fluorocarbon across its tool guides. At 1.84 mm, it is the cleanest documented starting point.
Diamond Copper Double Ā· 2.2 mm
Diamondās published copper-double tool guides include 1.8ā1.9 mm mono or fluorocarbon for the 2.2 mm sleeve. Treat it as a separate material, cavity, and pressure setup.
Deckhand note: Do not carry lighter-class sleeve or crimper settings into 1.84 mm. Confirm clean threading, use the exact manufacturer-specified cavity, and pull-test every completed leader before it goes in the bag.
Should I choose 30 m or 110 m?
The 30 m coil is the clean choice for a trip bag or a handful of leaders. The 110 m crew coil drops the cost per metre and makes sense when you rig often, carry backups, or prep for a full season.
How should I store the coil?
Keep it clean, dry, and out of prolonged light and heat. Return the coil to the UV-blocking metallized bag between trips and avoid kinking it under hard tackle.
Opsin Big Game Ā· 300 lb Ā· 1.84 mm
Rig it clean. Stay on the fish.
300 lb Ā· 30 m Ā· $119.99
