This is the assembly we use to make our L2062 7.5mm eyepiece. Six element design for sharp image from edge to edge. 40 degree field of view. Eye relief is 10mm, and exit aperture is 6.5mm. Coated optics. Front element clear diameter is 6mm and rear element clear diameter is 21mm. You may have other uses for it at our lower price. Not sure what the original design was for. They are marked "G.S.C. 249-100". Unused mint condition.