The Universal Magnifying Lens (also known as a diopter) replaces your 2x4" rear cover plate, ideal with our Carrera™ ArcOne® welding helmet, or with the included vertical and horizontal mounts for any manufacturer's 5x4" or 4x5" welding helmets. It provides magnification in increments of 1.00, 1.50, 2.00, 2.50 and 3.00.