The Greenough 4A fits well in any scenario, making it our most popular and well known design. From gliders to midlengths and in all conditions, the 4A is a surfer's best friend when it comes to single fin surfing. We like to refer to the 4A as the benchmark in fin design for its reliable speed and maneuverability and a great comparison when experimenting with other templates. No matter where you find yourself, the 4A has got your back!