This Larry Allison Junior Dolphin Race Keel Fin at 7-5/8 inches in depth with a narrow tip design offers better hold for a quick release in Flatwater still allowing for a low water drag. With a 7-1/4 inch base which gives you a fair base size for lateral resistance along with stability. Running a 4-1/4 inch rake for quick release. Has a little more up right leading edge at a 50 degree angle for quicker response but still able to shed through seaweed with ease. Total surface area of 47 sq inch.