Atomic Aquatic X1 Fin, X-Large, Silver Rigid Low-Profile Side Rails and shorter, stiffer blade make turning and pivoting easier Monocoque Structure and Power Plate is connected to the low-profile rails, efficiently transferring power from the leg and foot to the rails. Asymmetrical Blade Bend Flexing is better for alternate kick styles. Scissor kicks, frog-kicking and helicopter turning in tight circles put more emphasis on the up-kick or return stroke Vertical Stabilizers, or Strakes, add stability and lower drag to keep the fin tracking straight as an arrow Exclusive EZ-Lok Buckle System lets you easily snap the buckle on and off.