ANATOMICAL DESIGN: the Seac One scuba mask features an anatomical skirt made of high quality hypoallergenic liquid silicone that follows the shape of the face and sensitive to the skin PRESCRIPTION LENSES: Seac One easily becomes a prescription scuba mask thanks to optical lenses for myopia (nearsightedness) from -1.0 to -6.0 (sold separately, according to your prescription) PRACTICAL AND RESISTANT: polycarbonate frame, symmetrical lenses in tempered glass, resistant strap and easy to adjust thanks to the buckle with "Easy Touch" system PROTECTIVE CASE: Seac One has a special transparent case that can also be used for other diving masks