This leisure fin for free diving activities increases swimming comfort without loss of power. A window in the blade allows an ideal distribution of the effort to facilitate swimming on the surface of the water. The foot pocket is the ergonomic result of a deep research providing flexible and thin material on sensitive areas and thick sections on the power transmission zones. The result is a very light and comfortable fin, allowing longer diving periods without fatigue or muscle trauma. Since the product was brought to the market, fin orders have increased by 80 percent.