FCS II Skindog Performance Core Surfboard Side Bytes - Medium A high performance side fin designed by 11x European Champion Ben Skinner. The fin template is built for speed and the aircore construction compliments his highly technical Thunderbolt signature range. No need for a plate and screw. Ability to adjust your fin position in the box mid surf. Easily insert or remove your fin in seconds. No fin key required. Designed to be used in most existing Longboard boxes. No new box required.