Cleaning and maintenance work, as well as installation and repair of scientific, research, navigational, surveying, photographic, cinematographic, audiovisual, optical, weighing, measuring, signaling, detection, testing, checking, rescue, and teaching apparatus and instruments, apparatus and instruments for conducting, switching, transforming, accumulating, regulating, or controlling the distribution or use of electricity, equipment and instruments for recording, transmitting, reproducing, or...

Cleaning and maintenance work, as well as installation and repair of scientific, research, navigational, surveying, photographic, cinematographic, audiovisual, optical, weighing, measuring, signaling, detection, testing, checking, rescue, and teaching apparatus and instruments, apparatus and instruments for conducting, switching, transforming, accumulating, regulating, or controlling the distribution or use of electricity, equipment and instruments for recording, transmitting, reproducing, or...