Fire Extinguishers and Parts Therefor; Equipment for Use in Rescue in Mine and Other Disasters, Specifically Portable Resuscitators and Lung Ventilators; Electrical and Electronic Welders and Cutters for Metal; Teaching Aides, Models, and Motion Pictures; Teaching Machines; Dispensers for Measured Quantities of Welding Wires; Electrodes for Electric Arc Welding and Holders Therefore; Electrical Grounding Clamps; Helmets and Face Masks; Safety Spectacles and Goggles for Protection Against Accidents and Injury; Welder's and Observer's Screens, and Lenses Therefor; Electric and Electronic Monitors for Checking and Remotely Controlling Industrial Operations; Automatically Operated Valves (Not Being Parts of Machines); Pressure Gauges and Regulators; Electronic Gas Detectors and Monitors; Leak Detectors; Ionization Gauges; Vacuum Gauges; Spectrometers; Ion Accelerators; General Purpose Measuring Instruments; and Magnets