Designed to fit over frames not larger than 131mm X 48mm. The frame has a softly curved lower edge perfect for square or rectangular frames. The Navigator is constructed of hypoallergenic nylon for comfort and durability. The Polar Dynamix, or PDX, lenses are designed to eliminate glare and to block harmful UVA and UVB rays producing superior visual acuity. All Fitovers come with a complimentary case, cleaning cloth and neck cord.