Mizuno GX Sonic Racing Swim Cap PLUS - over ear design created for speed with a 3D molded design and textured surface to reduce resistance. World Aquatics Approved: Approved by World Aquatics for national and international swimming competitions. World Aquatics approved racing swimsuits have a unique FINA barcode printed on the swimsuit, making it easily identifiable to swimming officials. 100% Silicone 3D Formfit : Built with a 3D mold to contour to the swimmer's head shape, offering optimal hydrodynamics. GX-SONIC Series: Mizuno's most elite swim product, built for competition.