Single Tab eller Futures Fins System
Unlike the FCS, Futures use a single-tab system for its fins. Each of the fins is secured with an angled screw. ... Futures fins are designed with performance and durability in mind.
Single tab fins - the back of each fin box has a latch and the front of each box has a set screw that you have already loosened. The back of each single tab fin has a groove. Drop the back part of the fin into the box and push back as you lower the fin, hooking the latch on the box into the groove of the fin.