Don’t let Siege’s bold full square shape scare you. Protection is its core characteristic, as it withstands the same impact level as our styles in the ANSI Z87.1+ range. The reduced side coverage lightens the profile without sacrificing the strength of 100% UV protection. The frame features our one-of-a-kind Gargoyles G-Loc hinges, made of high-grade TR90nzz and tested at over 11 times stronger than TR90, a material commonly used in regular sunglasses. All Gargoyles lenses are ballistic-rated to meet or exceed ANSI Z87.1+ impact and optical standards and feature anti-reflective and oleo-phobic treatments to repel water, resist smudging, and make cleaning easier.TR-90 NZZ frame material.