The FCS II CI Upright Tri Fin Set – Medium is a high-performance thruster fin designed in collaboration with Channel Islands Surfboards. Perfect for surfers seeking instant speed, tight turns, and maximum responsiveness, this upright fin template excels in punchy, hollow waves and delivers quick drive right from takeoff.
This fin is especially well-suited for performance shortboards, hybrids, and step-down models with flatter rockers—boards where fast pivot and vertical surfing are key. With a full-bodied outline from base to tip, the CI Upright allows you to push hard through turns while still feeling loose and free off the top.
This medium-sized set is ideal for surfers in the 145–175 lb (65–80 kg) range, providing a great balance of control, drive, and agility across a variety of conditions.
Key Features:
- Template: Upright shape for quick rail-to-rail transitions and tight arcs
- Performance: Fast, loose, and drivey with immediate start-up speed
- Ideal Conditions: Steep, hollow waves and punchy beach breaks
- Fin Setup: FCS II Tri Fin (no screws required)
- Construction: Performance Core for speed and lightweight strength
- Designed For: Channel Islands hybrids and performance models
Medium Size Fin Specs:
- Fin Type: MED Side / MED Center
- Base: 4.39" / 111.4 mm
- Depth: 4.59" / 116.4 mm
- Area: 15.04 in² / 9700 mm²
- Sweep: 30.3°
- Foil: Flat
Fin Family – Reactor:
Speed. Snaps. Tight Turns. The CI Upright is part of the Reactor family, offering maximum responsiveness, quick direction changes, and vertical surfing right in the pocket.
The FCS II CI Upright Tri Fin Set – Medium is a go-to for surfers who want fast acceleration, tight pivot, and dynamic performance in high-speed conditions.
Why Shop at Rider Shack?
Rider Shack is a small, family-run surf shop committed to curating the best gear for real surfers. We handpick performance equipment that we trust, use, and stand behind. When you shop with us, you’re not just getting premium fins—you’re getting personal service, expert guidance, and gear that elevates your sessions.
Upgrade your ride with the FCS II CI Upright Tri Fin Set – Medium—built for power, precision, and high-performance surfing.
