These linear polarised lenses are of superior quality, mounted in aviation-style, black plastic frames, with hinged arms. Lenses are 0.254mm of polariser film. Polarised glasses contain light Gray filters for viewing slide shows, multi-media displays, concerts, movies, and ride simulators. Linear polarised filters are cut at opposing 45-degree angles, which unless otherwise requested are at 45 + 135 deg. ; e.g. if the right image is blackened by double polarisation, then after turning the glasses anticlockwise by 90 deg. , the left image is blackened. Polarising sunglasses have both lenses mounted identically and they have a weaker polarising effect.