Description Durable, light weight nylon material 3.85" x 1.70" viewing area Protects against UV and infrared radiation in variable shades from DIN9 to DIN13 Lens automatically darkens when arc is struck and returns to normal when welding stops Powered by solar cells with Auto Battery back-up Replacement Lenses: Part #41261 Replacement Headgear: Part #41263 Switching Time: Light to Dark 1/30,000 of a second (0.0000.33 sec.)