Radnor 2" X 4 1/4" 2.5 Diopter Polycarbonate Magnifying Lens With Universal Adapter Radnor 2" X 4 1/4" 2.5 Diopter Polycarbonate Magnifying Lens With Universal Adapter Designed to fit Radnor and most manufacturer's welding helmets| Get to those hard to see areas or use for jobs requiring detailed work