Taylor, Taylor, & Hobson, and Lee, H. Lenses comprising three single lens components have the middle double concave lens placed symmetrically, or approximately so, between the two outer double convex lenses and have the glasses of at least two different dispersions and of a refractive index for the D-line greater than 1.61. The item is pre-owned and in great to excellent vintage. You will find all necessary information in the item description. The images enclosed are with fine details and clearly visible and allowing making your own judgment. We will always mention, in my description ...