The Greenough 4-A Single Fin is the most iconic, functional and versatile single fin available, because it works extremely well on just about every type of surfboard. The 4-A has been True Ames' bread and butter for over 40 years now, and it is still the most popular single fin design there is due to it's all-around and well-balanced performance.

Form: Medium profile, full base coupled with a tapering & moderately flexible tip
Function: A fin that will hold when you need it to and release when the time is right
Feel: Neutral-positive, perfectly-balanced, a fin that will drive off the bottom, and have an acute responsiveness through arcing turns
Overall: Versatile - designed for all board shapes and surf conditions