Jaegers catalog #10D 1637. Cemented achromatic doublet, fully coated. Edge thickness is 5mm, center thickness is 6mm. These are in the original box from 1953 labeled "Nomenclature lens, erector, stock# F289-7575154, ORD DWG# A.7575154, packaged by Liberty Owens Ford". Unused, we have quite a few if you want to incorporate them into your project!