HVMLP-Set Premium Replacement Glass Plate Lens set for Optivisor and other similar models, this set comes with 4 lenses of varied magnification 1.5x,2x, 2.5x, 3.5x lens with storage case, Hand Finished Prismatic Glass lens set with focal length ranging from 20" with the 1.5x to 4" Focal length/working distance with the 3.5x lens, these are highly scratch resistant compared to acrylic lenses. Highly polished prismatic Glass lens set these will fit our HVM-3 and HVM-4 models they will also fit many other headband magnifiers including OptiVISOR® Brand.