37 Installation, maintenance and repair of lasers; installation, maintenance and repair of laser apparatus, machines and systems for marking, writing, printing, cutting, curing, drilling, machining, engraving, perforating and welding; installation, maintenance and repair of laser apparatus, machines and systems for surface and materials treatment; installation, maintenance and repair of lasers for industrial use, lasers for marking, writing, printing, cutting, curing, drilling, machining, engraving; installation, maintenance and repair of perforating and welding lasers for surface and materials treatment, lasers for scientific and measuring use, laser beam sources and laser systems, CO2 gas lasers, solid state lasers, diode lasers, picosecond lasers, laser beam sources for apparatus, machines and systems for marking, writing, printing, cutting, curing, drilling, machining, engraving, perforating and welding, laser beam sources for apparatus, machines and systems for surface and materials treatment; installation, maintenance and repair of power supplies for lasers, components and parts for lasers and laser beam sources; installation, maintenance and repair of lasers for medical, surgical, dental and cosmetic use, apparatus and systems for applying laser radiation and light for medical, surgical, dental or cosmetic use; information, advisory and consultancy services relating to the aforesaid