I of C slide rule

Data:

• R = P/10 , Q = P/5
  Q is shifted. R = 10 corresponds with Q = 17.5. Maybe this factor equals π/180 = 0.017453... (radian to degrees) Andries de Man
• The base is made of metal

Questions:

1. Where was it made ?
   A search of the scales in Herman's Archive gives no results. Andries de Man
   
2. What did it serve for ?
3. How does it work ?
   U and S and the scale below S are in degrees, for which T gives the sine (sin 30° = .50) The scales on the lower edge are also in degrees, for the other two quadrants. Andries de Man
   
4. What is the purpose of the two windows in the bottom ?
5. Who made it ?
   
   You might want to download the image of the logo and add it to an image-based query.
   Trademark search: 
   • EUIPO:
   Nice Class 9 (apparatus and instruments for scientific or research purposes, audiovisual and information technology equipment, as well as safety and life-saving equipment)
   Nice Class 16 (… drawing materials … instructional and teaching materials …)
   Vienna class 27.5.1 (letters presenting a special form of writing)
   Vienna class 27.5.5 (letters containing written or typographical matter)
   Vienna class 28.11 (inscriptions in Latin characters)
   Vienna class 28.19 (inscriptions in other characters)
   Trademark name starts with I
   Trademark name contains C
   GO!
   • USPTO Trademark Search:
   Goods and Services: instruments
   Design Code: 29.01.07 (small, inconspicuous design elements functioning as punctuation or parts of letters)
   Combined Mark: I*C*
   Copy this: GS:instruments AND CM:I*C* to the input box of USPTO Trademark Search
   (you might want to select "Wordmark" instead of "General search")
    
   • WIPO Global Brand Database does not allow external form submissions, so you're on you own!