safety goggles with ir protection for welders and gas cutters spec lens material should be mad e of polycarbonate with thickness 1 8 to 2 0 mm and filter shade 5 with anti fog and anti scratch coating on both s ides it should protect eyes from ultraviolet rays goggles should have indirect ventilators for air movement it sh ould be provided with adjustable elastic head band the frame material should be mechanically strong and weight of goggles not more than 100 gm it should have a universal fit