3.5x extra glass prismatic lens for Optivisor Headband Visors & HVM-3 and HVM-4

New or Replacement Lens, for Binocular Headband Magnifying Visor Prismatic Glass 3.5x lens with 4" Focal length/working distance  for binocular headband magnifier,  these will fit our HVM-3 and  HVM-4 models only they will also fit all OptiVISOR®  Brand models. They are easily replaceable simply push out mounting pins, and install new lens plate, and push in mounting pins or screws to lock in new lens.