The Huygenian eyepiece consists of two plano-convex lenses with the flat side facing out. Eye lens dia=1.4cm, f=3.5; field lens dia=3.0, f=6.5
The assembled eyepiece. There are no markings.
The objective lens is a single plano-convex lens. There is only one lens with this instrument. It is marked "|||"Diameter = 0.5cm, f=1.6cm
The objective screws into the distal end of the microscope nosepiece.