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FCS II H4 Tri-Fins



FCS II H4 Tri-Fins

Radically different side & center fin templates create a powerful fin set with ultimate speed & drive.

  • SIDE FIN PROFILE: Lower section produces maximum acceleration, while hatchet like tip creates stability & control.
  • CENTER FIN PROFILE: Highly raked elliptical outline reduces drag, and offers feeling of predictability when releasing through turns.
  • FIN FOILS TEMPLATE: Thicker base with tapered tip optimizes flex & regulates the release of energy during rail to rail transitions.

Ideal Conditions

  • A wide range of conditions, particularly good in critical overhead waves.

Board Types

  • Designed to fit the FCS II Fin System.
  • Recommended for performance shortboards with moderate-to-low rocker.

Fin Family

  • Accelerator: Find Control. Speed, flow and response with added control.


  • PRECISION SWISS ENGINEERED: Creates perfect synergy between fin geometry & HI-FI materials, giving smooth & predictable feel.
  • HIGH DENSITY UNI-DIRECTIONAL CARBON FIBER: Light & super strong with custom orientation to transfer more of your energy into speed than any other fin.
  • DYNAMIC TRAILING EDGE: Internal composite morphs under extreme load, enabling the fins to be pushed harder without sliding out.
  • INNOVATIVE PRODUCTION: Highly specialized robotic automation combined with camera assisted quality control, ensures absolute accuracy. 

SMALL (55Kg - 70Kg / 120 - 155 Lbs)
MEDIUM (65Kg - 80Kg / 145 - 175 Lbs)
LARGE (75Kg - 90Kg / 165 - 200 Lbs)


Base (inches)

Base (mm)

Depth (inches)

Depth (mm)

Area (inches)

Area  (mm)

Sweep Deg°


SML Side  4.36 110.6 4.34 110.1 14.29 9221 38.3° Flat
SML Ctr 4.29 108.8 4.49 113.9 13.82
8917 37.2° 50/50
MED Side 4.48 113.6 4.45 113.0 15.07 9721 38.3° Flat
MED Ctr 4.40 111.7 4.61 117.0 14.58 9405 37.2° 50/50
LRG Side
4.59 116.5 4.57 115.9 15.84 10221 38.3° Flat
LRG Ctr 4.52 114.6 4.73 120.0 15.33 9893 37.2° 50/50
Returns & Exchanges



We accept unworn, unused merchandise purchased from the Jack's Surfboards website in its original packaging with tags included for a refund of the product. Original shipping charges are non-refundable. You have 30 days from the delivery date to return your goods.


All Gift Card Sales are Final – No Refunds Or Exchanges

Shipping & Processing

Processing Time for orders shipping with ground or economy shipping is 1-3 business days. Orders placed with expedited shipping options and international orders will be shipped same-day or the next business day if placed after 12:00 pm PST.

Regular Jack's order fulfillment hours are Mon to Fri, 9 am to 5pm. We ship from our distribution center in Huntington Beach, CA.

Any orders placed on the weekend or during holidays will begin processing on the next following business day (excluding holidays)

Free Store Pickup

Now available at select Jacks. locations. Shop online and get your order fast at your local store. More Details


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