In solid-state laser machines and systems, the lens is protected against impurities by a protective glass. This serves as a pressure window for the cutting gas used and at the same time keeps spatter, smoke residue and steam away from the lenses. Not every protective glass can withstand this pressure. Genuine protective glasses from TRUMPF are produced according to precise specifications to meet the wavelength of the laser light and the requirements of the cutting and welding processes, as well as the sensor system. A special coating as well as the use of particularly pure materials guarantee a low degree of reflection and absorption and prevent thermal changes to the glass. Genuine protective glasses form the foundation of reliable cutting and welding processes.