In many auto-darkening helmets, this knob may be located at the left aspect of the welding helmet. It permits the welder to regulate the depth of darkness relying on the sort of welding they're acting. Welders need to usually use the darkest color advocated for the particular form of welding being carried out. Once you experience which you have adjusted the welding helmet to your liking, you have to position the helmet on and adjust the headband to ensure that the welding helmet still fits well. You have to also lower the helmet and adjust the angle until you may see thru the protect without any obstructions. Before beginning to weld, you should test the helmet’s car-darkening protect to ensure that it's miles nicely set. If your welding helmet has been beautifully set the lens will darken despite the fact that your head isn't always facing the arc. If for any purpose your lens doesn’t darken you must no longer use that welding