FINIS Swimming Positive Drive Size [L] * Can be used with a feeling of M size. Men with larger feet can enjoy a tight fit. (In my opinion, this is around 25-28 cm, but those with smaller feet can also adjust the rear strap for a tight fit. I have confirmed this by trying them on land.) Stroke training fins compatible with all 4 swimming strokes. The oval blade provides appropriate propulsion for all kicking styles. The short, wide blade design improves foot speed and ankle flexibility, enhancing the supination kick style. Ideal for individual medley training.