The single eyepiece has the Huygens design using two plano-convex lenses
The eyepiece is 37mm tall and consists of two plano-convex lenses with an aperture (dia=10mm) between them. Eye lens dia=9mm, f=18; Field lens dia=19mm, f=38mm.
The single objective is 10x/0.25 NA. Embossed on the body is "Spencer, Buffalo"