Used Mares X-Stream Open Heel FinsThe X Stream diving fins feature a blade length ranging from 34. 5 to 38 cm, depending on the size. These fins have an open foot pocket and are constructed using innovative, high performance materials. They offer superior thrust and minimize leg fatigue. The materials used provide maximum elasticity, high durability, and resistance to wear. The fins incorporate a special channel thrust system that enhances water movement and increases thrust