Welding masks are protective gear to block arc light generated during welding work and protect eyes and skin. Arc light is strong light at the center of sparks that occur during welding. It includes visible light that appears pale blue as well as strong ultraviolet rays that cannot be seen. It is said to adversely affect the human body, eyes in particular. Welding masks include handheld types, wearable types, and goggle types, each with black glass that blocks arc light. Automatic shielding masks have liquid crystal films that change brightness and light sensors that detect arc flickering. They usually look like ordinary transparent masks, but when arc light occurs, they instantly change to black glass and only the strong light of welding can be seen. They are convenient equipment as not only can both hands be used, but they can be constantly worn.