The Optical Insert has been specifically designed for the PROTOS® Integral Safety Glasses. It can be easily clipped to the bridge of the PROTOS® Integral Safety Glasses. Your optician can easily mount optical lenses up to +/-4 dioptres into the glass insert. The lenses are fully protected, as they are placed behind the protective glasses. A major advantage of the integrated glass insert is that no temples interfere with the ear protector, and hence do not exert any uncomfortable pressure on the head.