ForceFlexÂ® 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 ForceFlexÂ® safety glasses meet military MIL-PRF-31013 clause 188.8.131.52 for high velocity impact protection and exceed ANSI Z87+. 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 ForceflexÂ® eyewear is engineered to provide the highest level of innovation for consumers that demand the very best in safety.