FCS II Julian Wilson Tri Fin Set Julian Wilson's 'JW' signature fin featuring AirCore construction. Fast, Ultra Light with Quick Response. Overview Julian's new fin focuses on speed and projection for taking flight and adopting a more progressive approach while maintaining a feeling of predictability and control through longer arc turns. Updated in PC construction featuring our ultralight AirCore. Ideal Conditions Open face, down-the-line waves, particularly good in point and reef breaks. Board Types Designed to fit the FCS II Fin System. Recommended for performance shortboards with moderate-to-extreme rocker. Fin Family Carver: Find Power. Powerful, drawn-out turns with added hold. Performance Core + AirCore Fins with AirCore Technology feature a pressed polyurethane foam core that mimics the geometric foil of the fin. AirCore technology reduces the amount of fiberglass required in the RTM moulding process making it much lighter while allowing total manipulation of the flex.