The outer lens of these safety glasses flips down for welding, and when you're done, you simply flip them up. Nothing special. However, I've been wearing the previously-reviewed Mag-Safe safety glasses for years, and the Onix Plus is the only flip-up pair I've found that also has a reader's bifocal lens. The inside lens is available in two magnifying strengths (+1.5, +2.5), and outer lens in two different IR shades (3.0, 5.0). Makes it much easier for me to see while welding. Preferable to spending an arm and a leg for prescription safety glasses. Quicker than switching between protective eyewear and reading specs.