The fin box is the hardware that connects your fins to your board. Your box choice determines which fins you can ride, how fast you can swap them, and — on single-fin longboards — how much versatility you have across different wave conditions. This is a permanent decision once the board is glassed, so it's worth understanding the options before you order.
This guide covers the three practical systems we install — Futures, FCS II, and glass-ons — plus the two single-fin box lengths for longboards.
Why It Matters
You'll have this box system on the board for the life of the board. Every fin you buy, rent, or borrow has to match it. If you already own a stack of Futures fins from a previous board, ordering a board with FCS II boxes means re-buying your quiver. If you love a specific fin and never plan to change it, glass-ons give you the cleanest look — but you're locked in forever. Match the box system to how you actually ride, not what's fashionable.
Removable Fin Systems
The two mainstream systems are Futures and FCS II. Both are excellent; the differences are mostly preference and which ecosystem you're already in.
Futures (Our Default)
Futures fins click into a long slot on the bottom of the board. One bolt per fin secures them; takes about 30 seconds per fin to install or remove. The slot is visible on the bottom of the board but low-profile.
- Install: tool required (Allen wrench), one screw per fin
- Fin selection: massive — every major fin maker offers Futures-compatible templates
- Aesthetic: single visible slot per fin position, looks especially clean in white
- Cost: standard, no upcharge
This is what we default to on every order unless you ask for something different. It's the market standard for a reason.
FCS II
FCS II uses a keyless click-in system — the fin compresses and locks into two plugs on the rails, no screws, no tools. Faster to swap than Futures in exchange for a slightly different feel.
- Install: tool-free, push-and-click
- Fin selection: equally massive — every template available in FCS II format
- Aesthetic: two small round plugs per fin instead of one long slot
- Cost: standard, no upcharge
Blake rides FCS II personally because he's standardized his quiver around it and appreciates the tool-free install. Functionally it performs identically to Futures for the vast majority of riders.
Glass-Ons (Permanent)
The fin is glassed directly onto the board with fiberglass cloth and resin during lamination. No removable box, no hardware — the fin is structurally part of the board.
- Install: glassed in at build time, permanent
- Fin selection: one fin, picked at the time of order, never changed
- Aesthetic: cleanest possible look, no visible hardware anywhere on the bottom
- Cost: similar to removable, sometimes slightly more depending on the fin
- Trade-off: zero versatility — you're committed to that fin for the life of the board
Glass-ons are not practical for everyday boards because you can't tune the fin to the conditions. They're a great choice for signage boards (aesthetic is the point), wall hangers, and special builds where you've decided exactly what the board is for and what fin works best.
Single-Fin Box Lengths (Longboards & Gliders)
On a single-fin longboard, the choice is which length of box to install. This decision is about fin versatility, not performance.
Long Box (~10.5")
Accepts the widest range of fin templates — from 6" performance fins up to 10"+ classic pivot fins. Lets you experiment with different fins across different conditions without being locked to one template family. This is what we default to on longboards for good reason: ten years from now you'll appreciate the flexibility.
Short Box (~8.5")
A shorter box that only accepts fins specifically made for short boxes. Fewer fin options, less flexibility down the road. Only choose this if you specifically have a short-box fin you love and know you'll always ride.
Our recommendation: always go long box on a single-fin longboard. The short box limits your options for no meaningful benefit.
What We Default To
- Performance boards (shortboards, twins, mids, thrusters): Futures unless you specifically ask for FCS II.
- Single-fin longboards and gliders: Long box, single fin.
- Multi-fin boards with a specific fin the customer wants permanently: glass-ons on request.
If you're not sure, default to Futures on multi-fin boards and long box on longboards. You can't go wrong with either.
Blake's Take
The box system matters less than people think for how the board rides. Every modern system performs essentially identically — the differences are about which fin ecosystem you're in and how fast you want to swap. Pick based on what you already own or the install experience you prefer, not because someone told you one is "better."
Where this choice DOES matter is longevity. Glass-ons lock you in; removable boxes give you flexibility for the life of the board. For a board you'll ride daily, get removable boxes. For a statement piece, glass-ons can be the right move.