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Your cart is empty.F4 Propulsion represents the latest evolution of Military-style Fins from IST. Based on IST's iconic and military favorite F-1, the F4'swide blade design is slightly shorter however, there is no power shortage here. That s because of the expanded width rubber blade which incorporates unheard-of flexibility. Even more thrust is attained by 3 deep vents which force water backwards, emulating the effect of three synchronized turbo-powered water jets.
Benedict Beck
Reviewed in the United States on January 4, 2024
Seems like a decent quality fin, however a piece of plastic broke on one the buckles the first time I tightened it!
W. Seymour
Reviewed in Canada on May 15, 2022
I missed these fins!! To some feels like having 2x4’s on your feet. Well, leg strength as well as technique matter. I love these!!!
ted r.
Reviewed in the United States on February 27, 2022
Fit and comfortable
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