OPTIVISOR W/LENS 7 3 1/2X 4":MG-19057 Headband binocular visor with snap-in 3.5X magnifying lens plate for hands-free viewing Ground and polished glass prismatic lens for improved focus and reduced eye strain Visor size-adjustment knobs for customized fit 4" focal length for a variety of use Visor tilts out of way when not needed