Light diffusion class, when relating to welding helmets, describes what is generally referred to as clarity, or blurriness of an image. Our range of Diffusion Class 1 welding helmets includes helmets with lenses that provide a clear, uniform image, with no blurring or extra light diffusion in certain areas. If you have any questions or need a product recommendation, do not hesitate to contact our customer support team on 020 7501 0594 or via our Contact Us page.