Channel Islands CI Keel Fins

No, these are designed exclusively for the FCS II fin system. They feature a tool-less installation mechanism that clicks directly into FCS II boxes, so you cannot use them with traditional dual-tab boxes that require grub screws.

The CI Keel fins are designed to prioritize speed and flow, which helps a fish surfboard maintain momentum through flatter sections of the wave. The progressive flex pattern adds a bit more control during turns compared to stiffer, traditional keel fins, making the board feel more responsive.

These fins excel in small to medium-sized waves where generating speed is key. Their design helps you maintain flow in softer, mushier conditions, but they remain stable enough to handle steeper, punchier waves when you need to drive through a turn.

Yes, Performance Glass is known for its durability and stiff, consistent flex pattern. It provides a very solid, reliable feel underfoot, which is ideal if you prefer a fin that doesn't feel overly flexible or 'whippy' during aggressive maneuvers.

While they are optimized for fish shapes, you can certainly use them on other twin-fin or funboard setups. Just keep in mind that their keel shape is specifically tuned for the wide-tail, low-rocker characteristics of a fish, so they will significantly alter the drive and pivot of a more performance-oriented shortboard.