This is Edmund Scientific number 94,819. It is a cemented doublet that does not appear to be visually achromatic. Front ocal length is 120mm, back focal length is 90mm. Edge thickness is 8mm, center thickness is 11mm. This was probably one of the lenses used in a telescope eyepiece. Unused old Edmund stock! We think these were made to be the field lens for one of their famous RKE telescope eyepieces. The RKE design included a double convex eye lens and a special doublet field lens. See attached photos for the design info. You can do some fun experimenting with these.
