Extreme Maximum adaptability to all types of faces.Extreme made Seac mask history. Even today, it remains one of the best-selling models on the market, a benchmark for its ability to adapt to all types of faces and its maximum ductility. Frame: Polycarbonate Skirt: hypoallergenic liquid silicone Strap: Silicone Lenses: tempered glass Optical lenses: from -1.0 to - 6.0 Packaging: rigid transparent case included