LBTEK Achromatic Doublet Pairs are precision assembled from two cemented achromatic lenses, designed for applications such as relay imaging, NA conversion, and image magnification. These lens pairs are compatible with infinite conjugate conditions and also suitable for finite conjugate scenarios, where both the object and image planes are at finite distances from the lens pair. The lens pair is pre-installed in a threaded housing, with the housing surface engraved with the Item, focal length, and magnification for quick identification and installation. The integrated pre-assembled design allows direct integration into OEM systems, avoiding contact with exposed optical components. For use, position the lens with the shorter focal length toward the object side to achieve the nominal magnification; reversing the orientation yields the opposite magnification. When both lenses have equal focal lengths, either orientation provides 1:1 magnification.