FCS II Firewire Performance Core Thruster FinsFirewire FW shaper fin. A highly maneuverable fin providing exceptional stability through turns. Overview Designed by Dan Mann, the new 2020 Fire Wire template is an all round thruster set with shades of twin fin characteristics. Suited to Firewire models, the full bodied XL side fins produce exceptional hold and drive off the bottom, the smaller centre fin and unique tip design offers the projection of a twin and a surprising amount of release