Am Medium 
The AM  Medium  This fin's wider base provides increased drive through turns, making it ideal for high performance surfing. The center fin is smaller than the side fins for increased maneuverability.
 
side fins
Base:    4.50 inch
Height: 4.50 inch
Rake:    39.19 deg
 
rear fin
Base:     4.29 inch
Height: 4.31 inch
Rake:    37.78 deg