We have always considered and collected these commercial masks and helmets as industries tribal art. Examples can be elegant in their simplicity or bazaar and complex. They are always unique, suprising and filled with personality.
Optical pyrometers allow easy measurement of the temperature of objects that would normally be difficult to measure with contact devices. Examples are rotating components, hazardous materials, or high-electrical-field/high-voltage environments. This scope was made I'm guessing in the 1930s by Leeds and Northrup. It's in used condition.... On SALE at $40