AREA: This is the most important variable to consider when looking for fins. The fins area is basically the size of the fin, which is determined by the weight of the rider. A larger fin area will give you more hold and drive. A smaller fin area will have a looser feel.
BASE: The base has a direct effect on the drive of the fin. A larger base increases drive and acceleration, but it could make your board harder to turn.
HEIGHT: The higher the fin is the more hold it creates, making it ideal for bigger riders. A shorter fin will feel looser, with a quicker release .
RAKE: A longer rake will draw a wider turning arch, maintaining good holding power. This makes it ideal for Point break waves. A shorter rake will draw a quick and tight arch. This is ideal for pocket surfing and on punching beach breaks .
FLEX : the flexibility of the fin tip. A stiff fin is fast and responsive, although if it's too stiff it will make your board hard to turn. A flexible fin is more forgiving and offers a whipping sensation during turns, but it may make you feel as if you're losing control if it's too flexible.
CANT: The angle of the side fin is measured from a perpendicular line to the flat bottom of a surfboard. More cant will increase maneuverability and gives a loose feel. Less cant generates fast acceleration and stiffer feel. FOIL: The shape of the fin is measured from the front edge to the trailing edge and affects how water flows across it. The Hydrodynamic INSIDE FOIL has the capability to increase speed and drive which reduces drag, while the traditional FLAT FOIL offers good control of speed resulting in a quicker release in each turn.