A used Bergeon 4717 Flubacher F+C Measuring Lens and Magnifier 8x  

Magnification factor 8 x
Focusable Yes
Field of view 0.8 inch
Measuring length 0.6 inch
angles and radii
Optical characteristics Achromatic, distortion-free

Two colours scale for dark and light 
Dimensions 50 x 40 mm
Weight 80 grams
Case included

Made in Switzerland
Imperial scale included in delivery

This version offers graduations, radii and angles

Weight 80 grams