ForceFlex® FF1 technology incorporates a patented, multi-injection molding of the lens with a flexible Thermo Plastic Urethane (TPU) frame. Due to this construction, it can achieve a military ballistic level impact resistance at over 1000 feet per second. The TPU material allows the frame to flex and fit individual faces from large to small. All ForceFlex® FF1 safety glasses meet military MIL-PRF-31013 clause 3.5.1.1 for high velocity impact protection. This achievement benefits consumers by providing unparalleled levels of protection. The dual material temples combine Thermo Plastic Rubber (TPR) for comfort and polycarbonate for durability. MCR Safety's Forceflex® FF1 eyewear is engineered to provide the highest level of innovation for consumers that demand the very best in safety. These high quality safety glasses have a lifetime frame warranty and are engineered to provide the highest level of innovation. Choose the best safety glasses, choose MCR Safety! This product meets the ANSI/ISEA Z87.1 2020 standard.