蛙鞋

flippers \flippers\ n. {flipper} [By analogy with
flipper[W13(1)], the limb of an aquatic animal used for
locomotion]
A type of shoe with a paddle-like front extending well beyond
the end of the toe, used an aid in swimming (especially
underwater).

Note: They are typically of rubber-like material, and are not
worn when walking on land.

Syn: fin, fins.
[WordNet 1.5]