HVM-4SetXL is same as the HVM-4 Premium Binocular Headband Magnifier Visor, except it comes with a 4 Lens set 1.5x, 2x, 2.5x, 3.5x lenses and this model also comes with a 5x swivel eye loupe on the right eye. Headband is fully adjustable to fit any size quickly and easily, visor is also adjustable +/- 60 degrees either way making it easy to flip up and out of the way of the line of sight.The HVM-4Set has premium features including 4 lenses with magnification from 1.5x-3.5x, lightweight durable impact resistant visor shell and an aluminum alloy headband pivot mechanism as well as scratch resistant glass prismatic lenses, more suitable for the industrial environments. The 3.5x glass prismatic lens gives you an close working distance of 4" for most repetitive applications and hands free magnified view. 3.5x is the highest magnification for binocular (both eyes) magnified view, anything beyond 3.5x and the focal length is too close to see with both eyes. Can be worn over eyeglasses and many safety glasses. Other lens magnifications are available for purchase separately for the HVM-3 and HVM-4. Our standard size lenses will also fit many other headband magnifiers including OptiVISOR® Brand. If you currently have a Donegan Optivisor all of your lenses and accessories will fit this model.