Swim fins made between 1956 and 1962 by Dunlop Rubber Company for Aquafort range of underwater swimming equipment. According to Lillywhites' underwater catalogue of 1957, this product was "scientifically designed for maximum efficiency. Made by the original Frogmen suppliers with a two-way curved blade for power and open-ended semi-shoe gives comfort for all sizes 7-12. Fully adjustable heel strap and made with soft rubber to avoid strain on ankle."
<a href="//commons.wikimedia.org/wiki/User:Helmardine" title="User:Helmardine">Helmardine</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>