Tr90: TR90 is thermoplastic material produced in Switzerland it is incredibly durable| flexible| and lightweight Polycarbonate: Polycarbonate is lightweight| comfortable| impact resistant| and provides UV protection. Anti-slip| adjustable| non-allergenic rubber nose pads. Unique| adjustable pantoscopic tilt hinges with easily replaceable parts upon normal wear-and-Anti-slip| adjustable endtips with stainless steel core for professional adjustment at the opticians.