The Zentmayer microscope optics consists of a Huygens eyepiece (A) a drawtube (B), body tube (C), and objective (D).
This unmarked objective is approximately 20x magnification.
The eyepiece is the Huygens style consisting of two plano-convex lenses. Top lens: dia=11mm, f=20mm; Bottom lens: dia = 20mm, f=40mm.
The assembled eyepiece is 35mm tall.