The lens shade number tells you how dark or light something will appear through the lens of your helmet. This is measured using a system known as the American Welding Society (AWS) scale, and it ranges from numbers one to fourteen, with lower numbers representing darker shades and higher ones lighter shades.   So #14 represents very bright light while #0 represents near-total darkness. Most pancake welding helmets have a shade number of #13 or #12 which means they are perfect for anything from regular to low-level welding work.