TR90(Plastic titanium) material proportion 1.0(above 20% lighter than plastic frames) lightweight good elastic not easy to deformation high temperature resistant suitable for long time wearing. PC impact resistance of space lens: use PC space eccentric piece a kind of advanced material widely used in aviation equipment the most shock resistance lens in the world it can prevent the damage when doing sports break the lens more safe lightest super light heat resistance high optical transparency resistance to impact low birefringence ultraviolet-proof etc. six features. Impact resistance is 12 times higher than resin lens 60 times higher than glass lens 100% UV protction early stage widely used at aircraft bulletproof glass the astronauts face mask etc.