How to use:

• You pass each component through the slot of the base box or the fin box (if it uses the US system) and place them next to each other.
• You thread the cable-chain through the holes and secure it with a lock to the car's roof rack, at the beach, or wherever else you want to leave your board unattended.

This way, the two parts together cannot be removed from the box and you can rest easy. No one will take your surfboard off the rack.