Provides excellent optical quality and switching performance. User-selectable dark shades 8-12, four sensitivity levels for all types of arc-welding, and motion detector ON/OFF. Using new liquid crystal designs and manufacturing techniques, we were able to make the Speedglas™ SL auto-darkening filter much lighter than our other models, but with the same outstanding optical quality and switching performance. Thanks to its motion detector sensor the welding filter turns on as soon as you grab the helmet and then turns off automatically after fifteen minutes of non use. Speedglas™ Auto-Darkening Filter, Series: SL-Series, 1.68 in Window Height, 3.57 in Window Width, 8 to 12 Lens Shade