Swim fin (multiblade - against impact fin)

摘要

The flipper comprises a shoe-section with integral fins. The latter are elastic and of different lengths, bearing flat against each other. Where there are two fins, the length of one is between 1.5 and 2 times that of the other, it being situated above or below the latter. Where there are three fins, the middle one is the longest, the first of the others extending for least half its length, while the second is longer than this but shorter than the middle one. The fins bend for different amounts, opening and shutting in synchronism with the leg movements.