Zoggs Predator Flex S/M - Swim Goggle EXTREMELY COMFORTABLE: Super soft medical grade silicone is unique to our goggles. Allows for an extremely comfortable and super soft fit around the eyes for a more pleasing swim and won't cause headaches like traditional swim goggles. PATENTED INJECTED SILICONE FRAME: Allows for a lightweight, more durable frame than the leading brands. BEST ANTI FOG TREATMENT IN THE INDUSTRY: Our anti fog is part of the material of the lenses and is made as part of the lenses in the manufacturing process. DOUBLE HEADSTRAP: Split Head strap wraps around both the top and lower part of the back of the head, offering more security so that you don't lose your goggles when swimming. BLUE LENS TECHNOLOGY: Blue lens is a great tint to balance between sunny and dark weather conditions.