Made of German Schott optical glass and carefully surface-polished, the multi coats minimize reflection rate to its lowest and preserve accurate color balance and sharp image formation. Their super thin 3.1mm frames, made of hard anodic oxidized alloy, are compatible with all wide-angle lenses. Hoods and lens caps can be placed in front of the lens. MCUV filters prevent twisted image formation which is not noticeable with human eyes. Multi coats also keep the filter in good shape from water, dirt and scratches.