The Hydronamic fins are the latest creation from Bic Surf and use our widely praised Fin-Loc attachment system. Developed by Bic Surf R&D, the Hydronamic fins represent a vast improvement on conventional non-foiled surfboard fins. Conventional fins have a double foiled center fin with side fins that are flat on the inside. An inside flat surface running through the water is proven to cause unnecessary drag that slows down your speed and reduces reactivity. To solve this problem, we have given the inside edge of our Hydronamic fins a curved profile that allows water to run freely over the surface of the fin without causing drag, thereby increasing the speed of them through the water while not losing any of the control characteristics that the thruster fin configuration so successfully provides. The 10.5cm Fin-Loc fin is designed to fit the Fin-Loc boxes of: ACS & ACS Wahine - 5'10" / 6'7" / 7'3" / 7'9" - E-Comp - 6'2" / 6'10" / 7'6"