Frame Type: Rectangle Interchangeable Nylon, Frame Material: Grylamid, Lens Type: Polarized or Non-Polarized Polycarbonate or Glass, Zeal designs all of their ORIGINAL/UNIQUE frames in Moab, Utah. The inspiration for their unique frame styles comes from personal racing experiences and feedback from the hundreds of athletes that they sponsor & support.The material they have chosen for their frames is Grylamid because of its light weight to strength ratio. For performance eyewear, it is superior to any other available frame material. Grylamid contains no plasticizer in the manufacturing process, thus it effectively resists the damaging effects of perspiration, chemicals and temperature changes.Some of their frame styles incorporate thermoplast silicon nose pads and all of Zeal's glasses come with silicon temple ends. The virgin silicon used is inert & hypoallergenic. ?Delicate Fit, Massive Performance?Small-Medium Face Compatibility?Polycarbonate Tech, Cridalon Lens?Form &