Scuba Fins
Scuba fins or flippers are used underwater to propel the diver easier than they would be able to on their own. They attach to the feet securely and greatly increase the amount of surface area available for movement. When used correctly they can increase a divers speed ten fold.
Scuba fins are important because not only is it difficult to swim underwater anyway, but there is a lot of extra equipment that is difficult to maneuver with. Fins give the diver much more power allowing them to complete tasks with ease.
Scuba fins are basically the same but small innovations have been slowly coming. One of the best is a double fin on each fin for a total of four separate fins that allows for more spring in each kick as well as increase tight maneuvers and agility. They can be found anywhere diving equipment is sold, and at many major sporting goods stores.