Manufacturer: Aristo
Country of Manufacture: Germany
Type: 939/n=15 Stahlbeton
Number:  
Date of Manufacture: 1960+
Scales: (Front) M [b, k, r, sigmab] h
Scales: (Back) sigma'e, M [b, sigmab, r] Z, x, h
Number of Scales: 14
Gauge Points: π, 35.7, C, C1
Slide Rule made from: Plastic
Cursor made from: Plastic extra wide
Cursor Lines: 20
Overall Length of Rule: 33.7 cm
Length of Scales: 25 cm + 2.7 cm extension
Width: 4.8 cm
Depth: 0.4 cm
Weight: 122 gm
Acquired from: Dick Rose
Date: Jun 2001
Condition: Good
Accessories: 
 Cardboard box. Good condition
 Instructions (German). Good condition
 Data sheet.  Good condition
Comments: 
 An additional different cursor 939/n=10
 acquired from Bernhard Schneider Nov 2007