SecureFit Protective Eyewear features pressure diffusion technology that naturally adjusts to individual head sizes for a custom, natural fit as soon as you put them on. The self-adjusting construction adapts to each wearer & provides a snug fit that keeps the glasses securely in place as the wearer looks up & down or side-to-side to eliminate the need for frequent repositioning. Universal design eliminates the expense of stocking multiple frame sizes at jobsites to accommodate different people to keep your costs to a minimum. Impact-resistant polycarbonate lenses absorb 99.9 percent UVA & UVB rays up to 380 nm to maintain healthy vision when used outdoors. Anti-fogging properties help maintain visibility in hot & humid environments to help increase usage on the job.