Info on large 10kw bulb

[nkrames]

Hello all - thank you in advance for your time. https://imgur.com/a/9nmgQWO Photos of the bulb at this link

Any and all info helpful - can't locate much. No maker mark - Manufacturer, time period, use of this (I'm assuming movie set spot-lighting or some sort of general search/spot-light), etc. Metal base with a thick knit cloth between the glass and the metal, assuming to be an insulator. Assuming tungsten crystals/powder in the base? Lighting material appears "in tact" however a hairline crack along the upper portion. Acquired from someone who said they believe it to be 30s/40s - only markings are inside on the bottom of the glass, of MP 70, 10 KW and below that a seemingly 175 (maybe not 175, but instead R5?) with an nondescript symbol/letter after.

[nkrames]

Update/Edit - I believe it to be a late 20s/early 30s GE Mazda tungsten 10Kw similar to that referenced on this very site

Characteristics of Ten & Fifty Kilowatt Incandescent Lamps
by D.K. Wright & W.E. Forsythe
Lamp Developmental Laboratory, General Electric Company
http://www.bulbcollector.com/article010.html

There is an image of a 50kw iteration which appears identical in terms of filament structure, metal base with vertical slits and lack of tip. Only real difference I see is that of a shorter glass neck, which I'm assuming to be simply related to the difference in scale of the 10kw and 50kw .