This lens is 11/16" (18mm) diameter with a 5/8" (15mm) field of view.
It is held at the correct focal length above the scale by a plastic stand.
Knurled ring in the middle of the stand is the focusing ring.
The metric scale is graduated from 0 to 10mm in 0.1mm increments.
1-3/4 x 1-1/4 x 1-3/4"
Constructed of plastic, with an achromatic glass lens system.
Made in Germany.
Shipping weight 12 ounces.