Fins are your steering and hold, man! A single fin offers smooth, drawn-out turns classic to logging. Twin fins are loose, fast, and skatey, great for small waves. The thruster (three fins) is the gold standard—invented by Simon Anderson—giving you perfect balance of drive, speed, and control. Quads (four fins) offer insane speed and hold on bigger, hollow faces. It’s all about your style and the waves you’re chasing. Swapping fins can totally change your board’s feel.