FREE Shipping in the USA New foot pocket. No parachute effect The limiting factors in traditional open heel foot pockets are their weight and the “parachute effect”. When finning, water gets into the space between the bootie and the foot pocket, creating drag like the air in a parachute. The perforations prevent this and have the additional benefit of making the foot pocket very soft and flexible. Furthermore, the suction effect which can make doffing of the fins cumbersome, is now forever a thing of the past.