The Atomic Aquatics SubFrame Dive Mask is the strongest, most indestructable two window Atomic mask ever created. The strength is the result of an internal frame molded directly beneath the surface of the silicone skirt. As with all Atomic Masks, SubFrame provides incredible strength and rigidity, and also eliminates the bulky external plastic frame commonly seen in other masks. Features: Strong optical quality with distortion free Ultraclear lenses Prescription lens compatible Wide vision, low volume Soft Silicone provides a great fit and seal