The base of a ProBox fin has a set of V-notches onto which the grub screws land to create the downward pressure for a compression fit, when the grub screws are tightened.
Cant inserts are designed to create the desired fin cant angle. By removing and replacing the insert the cant angle is easily modified. The inserts are tapered to create a compression fit in the box when downward pressure is applied by the grub screws. Cant inserts are color coded to make angle identification simple. and come in 0° (BLUE), 4° (RED), 6° (BLACK), and 8° (WHITE) angles.
Each box has two grub screws that, when tightened, apply downward pressure on the fin base forcing the base and cant insert into the box creating a tight compression fit.
An Allen key is provided for tightening the grub screws.
ProBox is designed to provide a strong fin attachment in a surfboard. It has a patented insert mechanism that allows both cant and forward and backward adjustment. The box is designed to be simple to install, for this task it has special locator tabs that fix the box into the installation jig during the installation process. The boxes are molded from a tough polycarbonate material that is very durable.
The installation jig serves as the locator for the box, routing guide, and resin dam. It provides mating notches that lock the box tabs in place keeping the box securely located during the installation process. The jigs are flexible, inexpensive and reusable.