Silicone frames Glass lenses Anti-fog coating paint Advanced Tempered Glass Lenses: The lenses of the swim goggles are made of tempered glass with a safety film that provides good impact and scratch resistance. The safety film keeps the glass lenses from falling apart in case of accidental breakage, making them more secure and reliable. Let your child play unrestrainedly. Anti-fog clear, wide field of vision: The children's swimming goggles are treated with anti-fog to avoid fogging while swimming. The large one-piece window design provides a wide 180 panoramic view without blurring or distortion. Therefore, wearing the swim mask will provide a clear view of your child's underwater journey. Comfortable Silicone MaskOur mask is made of soft liquid silicone and the double gasket design provides a good seal and effectively stops water from entering. The children's snorkelling mask fits all face shapes and will not leave red marks on your child's face. In addition, the straps have a non-slip texture to ensure they do not slip off when swimming.